1 00:00:04,200 --> 00:00:08,200 'How often do you stop and really think about your food?' 2 00:00:08,200 --> 00:00:11,280 Look at all this lovely fat and sugar. 3 00:00:11,280 --> 00:00:13,120 Yummy. 4 00:00:13,120 --> 00:00:16,840 'Do you ever wonder why you eat what you eat, 5 00:00:16,840 --> 00:00:18,840 'What cooking does to food...' 6 00:00:20,160 --> 00:00:21,800 Delicious. 7 00:00:21,800 --> 00:00:24,400 '..or what effect it has on your body?' 8 00:00:24,400 --> 00:00:28,000 I trained as a medical doctor and I'm absolutely obsessed by nutrition 9 00:00:28,000 --> 00:00:30,640 and the hidden chemistry of food, 10 00:00:30,640 --> 00:00:34,440 so I've teamed up with botanist James Wong to explore food. 11 00:00:34,440 --> 00:00:37,920 Each of us coming from very different perspectives... 12 00:00:37,920 --> 00:00:39,760 Truly delicious. 13 00:00:39,760 --> 00:00:41,240 ..together we have taken over 14 00:00:41,240 --> 00:00:43,400 the country's leading food science lab... 15 00:00:45,560 --> 00:00:49,000 ..to deconstruct some of our favourite foods... 16 00:00:49,000 --> 00:00:50,600 It's all sunk to the bottom. 17 00:00:50,600 --> 00:00:54,000 ..and to reveal some truly remarkable secrets. 18 00:00:54,000 --> 00:00:58,240 I want to find out what effect food has on us and our biology, 19 00:00:58,240 --> 00:01:00,360 right down to the molecular level. 20 00:01:02,600 --> 00:01:06,480 As a botanist, I am fascinated by the massive diversity 21 00:01:06,480 --> 00:01:08,720 of edible plants on our planet. 22 00:01:08,720 --> 00:01:11,080 I'm going to put them under the microscope to discover 23 00:01:11,080 --> 00:01:14,680 exactly how their biology interacts with our own. 24 00:01:17,440 --> 00:01:19,360 So join us as we seek out 25 00:01:19,360 --> 00:01:23,280 the most remarkable food stories on the planet 26 00:01:23,280 --> 00:01:25,840 and reveal the hidden science of our food. 27 00:01:41,760 --> 00:01:43,360 We humans are peculiar. 28 00:01:43,360 --> 00:01:45,920 We eat foods no other animal would eat. 29 00:01:51,560 --> 00:01:55,200 On average, we spend 67 minutes a day eating. 30 00:01:56,720 --> 00:01:58,360 Which, over a lifetime, 31 00:01:58,360 --> 00:02:01,520 adds up to nearly three and a half years at the table... 32 00:02:03,440 --> 00:02:06,840 ..but we spend even more time thinking about food. 33 00:02:08,480 --> 00:02:12,520 When we're hungry, food begins to dominate our thoughts 34 00:02:12,520 --> 00:02:15,000 and, of course, our brains. 35 00:02:15,000 --> 00:02:18,240 And what's remarkable is we're beginning to understand exactly 36 00:02:18,240 --> 00:02:22,240 why certain foods create such cravings in us all. 37 00:02:23,760 --> 00:02:25,320 In this episode 38 00:02:25,320 --> 00:02:28,960 we'll be revealing how food really works on your brain, 39 00:02:28,960 --> 00:02:33,360 why we find some foods unbelievably delicious and delightful, 40 00:02:33,360 --> 00:02:36,640 but why others, well, they're quite frankly disgusting. 41 00:02:38,800 --> 00:02:43,120 This is the science that explains why food has such tremendous power 42 00:02:43,120 --> 00:02:45,160 over us and our behaviour. 43 00:02:53,000 --> 00:02:57,400 To start, how can we get a measure of how much our brains love or hate 44 00:02:57,400 --> 00:02:58,680 a particular food? 45 00:03:01,400 --> 00:03:04,520 Rather than eat, I'm going to use sight and smell alone to measure 46 00:03:04,520 --> 00:03:09,120 something we can't stop ourselves producing when we're around food - 47 00:03:09,120 --> 00:03:10,680 saliva. 48 00:03:10,680 --> 00:03:15,320 So, what I've got here is a little swab and it weighs 0.68g. 49 00:03:15,320 --> 00:03:16,720 Put that in there... 50 00:03:16,720 --> 00:03:19,840 and I've got what I'm told is a delicious meal underneath here 51 00:03:19,840 --> 00:03:21,200 so let's have a look. 52 00:03:21,200 --> 00:03:23,040 It doesn't smell delicious, I have to say. 53 00:03:23,040 --> 00:03:25,720 Oh, God! That's revolting. 54 00:03:25,720 --> 00:03:28,800 HE COUGHS It looks completely rancid, 55 00:03:28,800 --> 00:03:30,640 I have no idea what it is. 56 00:03:30,640 --> 00:03:33,360 'This is actually a delicacy in China. 57 00:03:33,360 --> 00:03:36,560 'It's a preserved egg called a century egg.' 58 00:03:36,560 --> 00:03:40,600 It reeks of ammonia and hydrogen sulphide, the smell of rotten eggs. 59 00:03:42,280 --> 00:03:44,640 So what will the saliva test reveal? 60 00:03:44,640 --> 00:03:48,160 In theory, the more I like the food, the more I should salivate. 61 00:03:49,120 --> 00:03:52,320 So, let's see what effect that has had on my... 62 00:03:52,320 --> 00:03:53,720 saliva. 63 00:03:56,280 --> 00:03:59,280 0.88, so it's gone up a little bit. 64 00:03:59,280 --> 00:04:01,440 I think that was in anticipation of something 65 00:04:01,440 --> 00:04:04,000 which turned out to be utterly revolting. 66 00:04:04,000 --> 00:04:06,800 I'm not producing much saliva. 67 00:04:06,800 --> 00:04:09,440 I really don't want to eat this. 68 00:04:09,440 --> 00:04:10,480 Right. 69 00:04:11,880 --> 00:04:14,640 Dish number two, which I am also told is delicious, 70 00:04:14,640 --> 00:04:16,920 although by now I'm deeply suspicious. 71 00:04:18,560 --> 00:04:19,880 Smells better anyway. 72 00:04:19,880 --> 00:04:21,840 OK, what is it? 73 00:04:21,840 --> 00:04:23,680 And it is chocolate cake, hurrah! 74 00:04:26,600 --> 00:04:32,200 Now, yeah, that smells nice and I can feel those... 75 00:04:32,200 --> 00:04:35,360 saliva flowing. Let's see if that has any measurable effect. 76 00:04:35,360 --> 00:04:40,560 Yeah, we are up to 1.83 this time, so lots of saliva there. 77 00:04:41,880 --> 00:04:44,000 For one of my favourite foods, chocolate, 78 00:04:44,000 --> 00:04:46,880 I produced about six times as much saliva. 79 00:04:47,880 --> 00:04:53,040 So this shows just how much the look and smell of food alone can fire up 80 00:04:53,040 --> 00:04:56,840 our brains and juice up our salivary glands. 81 00:04:56,840 --> 00:04:59,200 But why do we do it? 82 00:04:59,200 --> 00:05:03,920 Well, producing saliva helps us start digesting our food the moment 83 00:05:03,920 --> 00:05:05,800 it reaches our mouths. 84 00:05:05,800 --> 00:05:10,240 And that's because saliva contains digestive enzymes. 85 00:05:10,240 --> 00:05:14,040 And it's perhaps no surprise that I drooled over chocolate because the 86 00:05:14,040 --> 00:05:17,560 chemistry of chocolate makes it the world's most craved food. 87 00:05:24,080 --> 00:05:29,240 We Brits eat an average of almost 7.5 kilos of chocolate every year. 88 00:05:32,160 --> 00:05:35,360 The mere sight of it may be triggering feelings of desire 89 00:05:35,360 --> 00:05:36,760 in your brain right now. 90 00:05:42,800 --> 00:05:46,080 But just how does it create such strong cravings? 91 00:06:08,480 --> 00:06:12,520 I've come to Peru to discover how we transform chocolate from raw, 92 00:06:12,520 --> 00:06:15,080 bitter beans into bars of deliciousness. 93 00:06:18,480 --> 00:06:21,960 I want to understand exactly why we crave it so much. 94 00:06:33,240 --> 00:06:36,120 It's especially strange because in its raw state 95 00:06:36,120 --> 00:06:39,040 the cocoa plant is not at all what you might expect. 96 00:06:44,920 --> 00:06:47,080 Wow! Look at that. 97 00:06:47,080 --> 00:06:51,360 You break open this thick husk and you've got sticky ivory pulp 98 00:06:51,360 --> 00:06:52,880 that is... 99 00:06:52,880 --> 00:06:54,680 It is truly delicious. 100 00:06:54,680 --> 00:06:59,120 It has this incredible tropical flavour that's halfway 101 00:06:59,120 --> 00:07:03,440 between lemonade and a custard apple, if you've ever had that, 102 00:07:03,440 --> 00:07:05,720 sweet, acidic, sticky. 103 00:07:07,360 --> 00:07:09,080 I'm sorry for being gross, but... 104 00:07:10,480 --> 00:07:14,200 The bit that chocolate's made out of is the bean on the inside, 105 00:07:14,200 --> 00:07:16,600 if you were to spit it out. 106 00:07:16,600 --> 00:07:21,240 It's amazing that anyone thought that beneath sticky, sweet, 107 00:07:21,240 --> 00:07:22,640 delicious flesh, 108 00:07:22,640 --> 00:07:26,560 the rock hard super-bitter bean on the inside could make good eating. 109 00:07:29,920 --> 00:07:31,800 The processing of chocolate begins 110 00:07:31,800 --> 00:07:33,880 as soon as the pods are off the plant. 111 00:07:36,040 --> 00:07:38,200 They're left to ferment in their own juices... 112 00:07:39,440 --> 00:07:43,320 ..where naturally occurring yeast breaks down sugar into alcohol 113 00:07:43,320 --> 00:07:46,600 which, in turn, helps remove the bitter alkaloids from the beans. 114 00:07:48,800 --> 00:07:52,520 Then the beans are dried and they're still raw and quite bitter, 115 00:07:52,520 --> 00:07:54,760 nothing like the chocolate we know and love. 116 00:08:02,040 --> 00:08:03,720 What happens next will soon get 117 00:08:03,720 --> 00:08:06,360 my grey matter crackling with excitement. 118 00:08:07,520 --> 00:08:10,320 The beans are put in a kind of oven. 119 00:08:10,320 --> 00:08:12,600 What this does is it roasts the beans 120 00:08:12,600 --> 00:08:15,080 and that's really key to bringing out that kind of 121 00:08:15,080 --> 00:08:20,080 toasty, warm, characteristically chocolaty flavour. 122 00:08:20,080 --> 00:08:22,680 120 degrees, there they go. 123 00:08:25,280 --> 00:08:28,960 All this processing creates hundreds of new chemical compounds 124 00:08:28,960 --> 00:08:30,360 in the chocolate beans. 125 00:08:32,320 --> 00:08:36,600 And it's converting the otherwise odourless compounds into volatile 126 00:08:36,600 --> 00:08:40,960 aroma-bearing ones, which begins to explain chocolate's popularity. 127 00:08:42,280 --> 00:08:46,200 The roasted bean's still got these very fine thin shells on. 128 00:08:47,880 --> 00:08:51,080 They're going in here and you can actually see all the shells 129 00:08:51,080 --> 00:08:56,760 wafting up and, for the first time, you can suddenly smell chocolate. 130 00:08:56,760 --> 00:08:58,320 It's... 131 00:08:58,320 --> 00:08:59,960 Oh, it's good. It's really good. 132 00:09:04,440 --> 00:09:09,640 The comforting aroma of chocolate actually comes from 25 different 133 00:09:09,640 --> 00:09:11,040 smell molecules, 134 00:09:11,040 --> 00:09:15,640 like 3-methyllbutannic acid 135 00:09:15,640 --> 00:09:17,520 and dimethyl trisulphide. 136 00:09:18,800 --> 00:09:21,080 And the weird thing is, on their own, 137 00:09:21,080 --> 00:09:24,960 they're more reminiscent of body odour and cooked cabbage. 138 00:09:25,920 --> 00:09:28,040 But with so many types of molecules 139 00:09:28,040 --> 00:09:31,200 wafting out of the cocoa beans and assaulting our noses, 140 00:09:31,200 --> 00:09:33,120 our brains just can't separate them out. 141 00:09:34,640 --> 00:09:39,640 Instead, one combined glorious smell emerges, delicious chocolate. 142 00:09:44,200 --> 00:09:46,520 But aroma is just part of the story. 143 00:09:53,480 --> 00:09:56,880 Cocoa beans are incredibly rich in fat, 144 00:09:56,880 --> 00:10:00,440 roughly like 50%, and if you take a whole bunch of them and squish that 145 00:10:00,440 --> 00:10:04,480 fat out and get it to cool down to room temperature, you get this. 146 00:10:04,480 --> 00:10:06,920 This is cocoa butter. 147 00:10:08,320 --> 00:10:12,560 Cocoa butter is just one of many different types of fat, 148 00:10:12,560 --> 00:10:14,680 each with unique characteristics, 149 00:10:14,680 --> 00:10:17,880 which create pure pleasure when teamed with the right food. 150 00:10:19,240 --> 00:10:22,640 Imagine toast without butter, 151 00:10:22,640 --> 00:10:25,640 frying without oil 152 00:10:25,640 --> 00:10:28,160 or ice cream without, well, cream. 153 00:10:29,320 --> 00:10:32,760 Fat transforms our enjoyment of food and for good reason. 154 00:10:34,040 --> 00:10:37,480 Before agriculture, fat was a critical source of energy 155 00:10:37,480 --> 00:10:39,200 to our ancestors. 156 00:10:39,200 --> 00:10:43,200 So our brains may well have evolved to reward us with feelings 157 00:10:43,200 --> 00:10:44,920 of pleasure when we ate it. 158 00:10:47,960 --> 00:10:52,720 And we now know exactly where in the brain this pleasure is felt - 159 00:10:52,720 --> 00:10:56,040 regions like the lateral hypothalamus and the amygdala. 160 00:10:59,560 --> 00:11:03,080 We've even seen that the higher the level of fat in a food, 161 00:11:03,080 --> 00:11:05,560 the more active these parts of the brain become. 162 00:11:08,840 --> 00:11:12,080 Now, there's one national delicacy almost guaranteed 163 00:11:12,080 --> 00:11:14,000 to fire up your brain - 164 00:11:14,000 --> 00:11:16,600 Cornish clotted cream. 165 00:11:16,600 --> 00:11:21,360 It's a whopping 60% fat, the creamiest of all creams. 166 00:11:22,360 --> 00:11:24,800 But it may not have originated in Cornwall at all. 167 00:11:36,840 --> 00:11:38,800 I've come to Afyon in Turkey 168 00:11:38,800 --> 00:11:41,120 in search of the origin of clotted cream. 169 00:11:42,600 --> 00:11:46,520 It's one of the richest, most melt-in-the-mouth dishes in the world. 170 00:11:49,040 --> 00:11:53,320 But I'm also here to discover just why this type of fat has such 171 00:11:53,320 --> 00:11:55,200 a powerful effect on our brains. 172 00:11:56,960 --> 00:12:01,480 The fat I'm interested in is made from the milk of these animals - 173 00:12:01,480 --> 00:12:02,920 water buffalo. 174 00:12:05,320 --> 00:12:09,320 To make the creamiest fat, you need extremely rich milk, 175 00:12:09,320 --> 00:12:11,360 and to make that, water buffalo 176 00:12:11,360 --> 00:12:13,760 need to eat something pretty extraordinary. 177 00:12:22,680 --> 00:12:25,720 These are the poppy fields that surround Afyon. 178 00:12:29,200 --> 00:12:32,400 At the height of summer, the seed heads are harvested for the legal 179 00:12:32,400 --> 00:12:35,520 production of opiate-based medicines like morphine. 180 00:12:36,960 --> 00:12:40,560 What's left behind becomes fodder for the buffalo. 181 00:12:40,560 --> 00:12:42,240 Hi there. 182 00:12:42,240 --> 00:12:45,600 Along with hay, this is what these buffalo are eating. 183 00:12:45,600 --> 00:12:48,680 It's what's left over when they've taken the poppy, 184 00:12:48,680 --> 00:12:52,960 they've extracted the opium and sent it off to be turned into morphine 185 00:12:52,960 --> 00:12:54,200 and other painkillers 186 00:12:54,200 --> 00:12:56,400 and this is really what remains. 187 00:12:56,400 --> 00:12:59,400 Now, there's not going to be any opiate left inside it but it's said 188 00:12:59,400 --> 00:13:02,560 to be extremely nutritious 189 00:13:02,560 --> 00:13:05,520 and the reason they feed it to buffalo is it's said 190 00:13:05,520 --> 00:13:07,960 to add to the flavour, but particularly the sort of... 191 00:13:07,960 --> 00:13:09,560 the richness, the fatness, 192 00:13:09,560 --> 00:13:11,000 the oiliness of the milk. 193 00:13:14,960 --> 00:13:16,320 There you go. 194 00:13:17,400 --> 00:13:18,600 Oh, blimey! 195 00:13:20,760 --> 00:13:25,320 The poppy is packed full of natural oils and fats and some of this 196 00:13:25,320 --> 00:13:27,160 ends up in the buffalo's milk. 197 00:13:27,160 --> 00:13:29,600 Let's give it a go. 198 00:13:29,600 --> 00:13:31,320 HE GROANS 199 00:13:31,320 --> 00:13:32,360 Nothing. 200 00:13:32,360 --> 00:13:34,160 Sorry about that. 201 00:13:34,160 --> 00:13:35,200 Yeah, OK. 202 00:13:36,520 --> 00:13:38,960 HE LAUGHS 203 00:13:38,960 --> 00:13:40,120 I think I'll leave it to you. 204 00:13:41,400 --> 00:13:44,200 The milk produced by buffalo is extremely rich 205 00:13:44,200 --> 00:13:46,000 and has twice the fat of cow's milk. 206 00:13:47,440 --> 00:13:51,400 So here we go. That's the product of a bit of hard work - not by me, 207 00:13:51,400 --> 00:13:53,120 I have to say. 208 00:13:54,200 --> 00:13:58,760 This rich, oily milk will be turned into an ancient version 209 00:13:58,760 --> 00:14:01,360 of clotted cream called kaymak. 210 00:14:01,360 --> 00:14:04,160 - Merhaba! - Merhaba. 211 00:14:04,160 --> 00:14:06,160 This is where the magic happens, is it? 212 00:14:07,560 --> 00:14:10,240 Milk has a very particular chemistry. 213 00:14:11,240 --> 00:14:13,280 It's mainly fat and water, 214 00:14:13,280 --> 00:14:16,080 which together form what's called an emulsion. 215 00:14:17,520 --> 00:14:22,200 The fat is dispersed throughout the water in tiny globules. 216 00:14:22,200 --> 00:14:25,480 When it's heated, some of the water is evaporated off, 217 00:14:25,480 --> 00:14:27,560 leaving a higher concentration of fat. 218 00:14:28,600 --> 00:14:32,920 These globules become sticky and some bind together to form 219 00:14:32,920 --> 00:14:34,800 a delicate mesh on the surface. 220 00:14:36,080 --> 00:14:40,320 It's now a matter of letting it stand and gently cooking again until 221 00:14:40,320 --> 00:14:41,560 it's ready. 222 00:14:45,120 --> 00:14:47,960 Now, this is a very traditional way of making clotted cream and, 223 00:14:47,960 --> 00:14:51,720 in fact, it's pretty much how they make it down in Devon and Cornwall 224 00:14:51,720 --> 00:14:54,640 and that is perhaps because there is a link. 225 00:14:54,640 --> 00:14:58,080 It's said that the Phoenicians around 2,000 years ago 226 00:14:58,080 --> 00:15:00,560 brought this technique from this part of the world. 227 00:15:00,560 --> 00:15:02,440 They went to Cornwall in search of tin, 228 00:15:02,440 --> 00:15:04,800 what they left behind was clotted cream. 229 00:15:06,320 --> 00:15:10,800 So the great Cornish delicacy could have started life here in Turkey. 230 00:15:14,640 --> 00:15:19,040 This is kind of the end product, right? You stick your hands in. 231 00:15:19,040 --> 00:15:21,400 She's invited me to stick my hand in as well. OK. 232 00:15:21,400 --> 00:15:23,320 I have washed my hands, I promise you. 233 00:15:27,400 --> 00:15:30,440 So it's, erm, like sort of the finest soap. 234 00:15:30,440 --> 00:15:33,920 You can imagine sort of, you know, washing in it almost. 235 00:15:33,920 --> 00:15:36,640 It's got a very lovely sort of silky texture to it. 236 00:15:36,640 --> 00:15:38,400 OK, so I think... 237 00:15:38,400 --> 00:15:42,640 'Kaymak is 60% fat, three times that of single cream. 238 00:15:42,640 --> 00:15:46,160 'The way it feels on the tongue drives our brains wild.' 239 00:15:47,800 --> 00:15:51,520 So what is it that kaymak has that other foods are missing? 240 00:15:53,320 --> 00:15:57,000 Why is it so much more seductive than, say, butter? 241 00:15:59,160 --> 00:16:03,600 The way that kaymak is made obviously determines its structure 242 00:16:03,600 --> 00:16:07,160 and its structure in turn will influence what it feels like 243 00:16:07,160 --> 00:16:09,040 in my mouth, so let's give it a go. 244 00:16:10,280 --> 00:16:12,880 Oh, it's very smooth and creamy. 245 00:16:12,880 --> 00:16:15,400 I can feel it flowing across my tongue. 246 00:16:17,400 --> 00:16:21,440 The ease with which something flows is also known as its viscosity 247 00:16:21,440 --> 00:16:23,480 and that is something you can measure. 248 00:16:28,760 --> 00:16:32,760 This machine is a rheometer. 249 00:16:32,760 --> 00:16:36,640 It accurately measures viscosity at certain temperatures and pressures. 250 00:16:40,240 --> 00:16:43,920 And viscosity turns out to be the secret behind why 251 00:16:43,920 --> 00:16:46,160 kaymak is so good to eat. 252 00:16:48,160 --> 00:16:52,600 What is really striking about this graph is the collapse here at around 253 00:16:52,600 --> 00:16:56,000 24 degrees, when it goes from being sort of thick and solid and turns 254 00:16:56,000 --> 00:16:59,200 into a liquid. We did the same test with another fat, 255 00:16:59,200 --> 00:17:02,160 in this case it was butter and, as you can see there, 256 00:17:02,160 --> 00:17:07,240 butter begins to change at around 24 degrees but it's a much more gradual 257 00:17:07,240 --> 00:17:11,200 change and that may help explain why butter is not one of those things 258 00:17:11,200 --> 00:17:14,040 you like to take out of the fridge and sort of wolf down. 259 00:17:18,640 --> 00:17:24,280 Kaymak melts and flows more quickly over the tongue than butter, 260 00:17:24,280 --> 00:17:26,080 making it feel smooth. 261 00:17:27,400 --> 00:17:28,640 Dig in! 262 00:17:28,640 --> 00:17:32,600 'And it's this smoothness that our brains respond to, 263 00:17:32,600 --> 00:17:35,240 'via special receptors on our tongues.' 264 00:17:35,240 --> 00:17:36,600 Some kaymak. 265 00:17:40,760 --> 00:17:42,640 If you take a close look at your tongue, 266 00:17:42,640 --> 00:17:47,080 you'll see it's covered with lots of little bumps called papillae. 267 00:17:47,080 --> 00:17:48,920 On the surface of these papillae, 268 00:17:48,920 --> 00:17:52,840 you have taste receptors, but you also have touch receptors. 269 00:17:53,880 --> 00:17:56,800 Now if you eat something which is fat, 270 00:17:56,800 --> 00:18:00,920 then that fat contains tiny little globules which are so small, 271 00:18:00,920 --> 00:18:02,800 only a few microns across, 272 00:18:02,800 --> 00:18:07,640 that your touch receptors don't perceive it as different particles, 273 00:18:07,640 --> 00:18:10,520 they just see it as one thing, smoothness. 274 00:18:13,520 --> 00:18:16,880 Since fat triggers touch receptors on the tongue, 275 00:18:16,880 --> 00:18:20,920 you might think that the signals end up in the touch region of the brain. 276 00:18:26,080 --> 00:18:27,880 And indeed they do. 277 00:18:27,880 --> 00:18:32,680 But the signals also go to the area for taste so, oddly enough, 278 00:18:32,680 --> 00:18:38,360 the brain perceives the feel, the texture of fat as a taste, 279 00:18:38,360 --> 00:18:43,080 which helps explain why the texture of some fats is so important when 280 00:18:43,080 --> 00:18:46,160 it comes to creating these wonderful feelings 281 00:18:46,160 --> 00:18:48,760 in the pleasure centres of our brains. 282 00:18:48,760 --> 00:18:50,880 Thank you very much. Bye-bye! 283 00:18:58,320 --> 00:19:03,800 Chocolate, too, can drive the pleasure centres of our brains wild 284 00:19:03,800 --> 00:19:06,160 with its creamy, high-fat content. 285 00:19:08,920 --> 00:19:10,760 But until the 16th century, 286 00:19:10,760 --> 00:19:12,680 we wouldn't have given it a second thought. 287 00:19:16,000 --> 00:19:19,440 When the Spanish Conquistadores first arrived in the Americas, 288 00:19:19,440 --> 00:19:22,840 they found the indigenous people drinking a bitter mixture 289 00:19:22,840 --> 00:19:25,280 made from cocoa beans. 290 00:19:25,280 --> 00:19:28,200 The Spanish thought of adding one more ingredient that would make for 291 00:19:28,200 --> 00:19:30,200 something far more appealing. 292 00:19:30,200 --> 00:19:31,360 And they were right. 293 00:19:33,000 --> 00:19:36,480 That ingredient was lots of sugar. 294 00:19:36,480 --> 00:19:40,520 The addition of sugar to this mix is so crucial 295 00:19:40,520 --> 00:19:43,880 to our enjoyment of chocolate, because in nature 296 00:19:43,880 --> 00:19:47,640 sugar and fat are very rarely found together, 297 00:19:47,640 --> 00:19:49,560 at least in high concentrations. 298 00:19:52,240 --> 00:19:55,040 Fruits like strawberries are packed full of sugar. 299 00:19:58,200 --> 00:20:01,560 If you want fat, certain cuts of meat will give you a hefty dose... 300 00:20:02,960 --> 00:20:07,680 ..but if you want a mixture of both, and in relatively equal measure, 301 00:20:07,680 --> 00:20:11,400 there's just one place in nature that that can be found. 302 00:20:11,400 --> 00:20:15,960 It's only really in breast milk where you end up with this perfect fusion 303 00:20:15,960 --> 00:20:21,040 of 50% of the calories coming from sugar and 50% coming from fat. 304 00:20:22,800 --> 00:20:26,840 So our craving for chocolate goes back to the first moments of life... 305 00:20:28,360 --> 00:20:29,640 ..your very first meal. 306 00:20:31,640 --> 00:20:33,360 And that craving stays with us. 307 00:20:38,520 --> 00:20:42,520 If you think about almost all the foods that just drive people crazy, 308 00:20:42,520 --> 00:20:46,600 you know, cookies, doughnuts, cheesecake, ice cream, 309 00:20:46,600 --> 00:20:48,240 if you look at the recipes, 310 00:20:48,240 --> 00:20:52,600 almost all of them have a rough 50/50 split in terms of calories 311 00:20:52,600 --> 00:20:57,240 between sugar and fat. It's that golden formula that just basically 312 00:20:57,240 --> 00:20:59,680 sends off all the pleasure signals in our brain, 313 00:20:59,680 --> 00:21:01,440 making food just irresistible. 314 00:21:02,960 --> 00:21:06,840 It's a comforting chemical composition that we biologically 315 00:21:06,840 --> 00:21:08,720 are set up to love. 316 00:21:13,520 --> 00:21:18,320 So what exactly are chocolate and other fat and sugar-filled foods 317 00:21:18,320 --> 00:21:23,520 with that magic 50/50 ratio actually doing to our brains? 318 00:21:23,520 --> 00:21:27,080 Why do these foods become almost addictive? 319 00:21:28,440 --> 00:21:33,000 Even as I look at all this lovely fat and sugar, 320 00:21:33,000 --> 00:21:35,080 I'm beginning to drool. 321 00:21:35,080 --> 00:21:38,240 My own weakness is our very own version of kaymak... 322 00:21:40,640 --> 00:21:43,840 ..clotted cream at the heart of a cream tea. 323 00:21:43,840 --> 00:21:46,520 I've even got a little bit of a shake. 324 00:21:46,520 --> 00:21:49,800 Our desire to eat as something as delicious as a cream tea... 325 00:21:52,160 --> 00:21:57,080 ..and why we crave it over and over again has been mapped in the brain. 326 00:21:57,080 --> 00:21:58,120 Mmm! 327 00:22:04,760 --> 00:22:07,480 Now I'm getting sensory overload. 328 00:22:07,480 --> 00:22:09,640 It releases a whole 329 00:22:09,640 --> 00:22:10,920 host of flavours in my mouth. 330 00:22:12,800 --> 00:22:17,480 There's also loads of things clicking off in my brain, 331 00:22:17,480 --> 00:22:20,280 and I'll show you here just what's going on. 332 00:22:20,280 --> 00:22:24,120 What's happened is the pleasure I get from cream teas 333 00:22:24,120 --> 00:22:26,200 has activated an area here. 334 00:22:28,760 --> 00:22:33,440 Because, just like kaymak, it all begins in the amygdala, 335 00:22:33,440 --> 00:22:35,880 the area in our brain which is the core 336 00:22:35,880 --> 00:22:39,000 of our emotional response to food. 337 00:22:39,000 --> 00:22:42,880 It, in turn, triggers something called the reward pathway, 338 00:22:42,880 --> 00:22:47,320 part of which is the nucleus acumbens. 339 00:22:47,320 --> 00:22:49,600 This is where desire forms. 340 00:22:49,600 --> 00:22:51,680 I like it, I want it, I want more of it. 341 00:22:54,080 --> 00:22:57,760 The desire centre creates the motivation to eat again 342 00:22:57,760 --> 00:23:01,440 by activating two other parts of the reward pathway. 343 00:23:02,720 --> 00:23:05,280 This area here is where memories are laid down. 344 00:23:05,280 --> 00:23:07,440 It's called the hippocampus. 345 00:23:07,440 --> 00:23:09,720 Memories I'm building up from this occasion, 346 00:23:09,720 --> 00:23:13,600 being here in a nice tea shop on a sunny day in London. 347 00:23:15,280 --> 00:23:19,200 My brain is creating a strong memory of the pleasure of eating 348 00:23:19,200 --> 00:23:23,560 a cream tea so I'll remember it in future and want it again. 349 00:23:25,120 --> 00:23:27,520 This area of the brain is different, 350 00:23:27,520 --> 00:23:29,920 it's more complex. It's the frontal lobe. 351 00:23:29,920 --> 00:23:34,120 This area controls our behaviours and planning. 352 00:23:35,280 --> 00:23:38,440 When the desire centre signals to this region, 353 00:23:38,440 --> 00:23:40,720 it's reinforcing the sequence of behaviours... 354 00:23:42,480 --> 00:23:46,280 ..the exact procedure required to get hold of a cream tea. 355 00:23:48,200 --> 00:23:50,760 Should you see any one of these things again, 356 00:23:50,760 --> 00:23:54,960 you'll be reminded of how much you enjoy cream teas 357 00:23:54,960 --> 00:24:00,520 and you'll know exactly what you need to do to get it. 358 00:24:00,520 --> 00:24:03,320 It's your brain's way of motivating you, 359 00:24:03,320 --> 00:24:06,600 ensuring that the pleasures you experience in the present 360 00:24:06,600 --> 00:24:08,320 are repeated in the future. 361 00:24:10,760 --> 00:24:15,480 Of course, many foods have an impact on the reward pathway. 362 00:24:15,480 --> 00:24:19,920 But new research is revealing how one drink in particular can actually 363 00:24:19,920 --> 00:24:22,240 magnify its powerful effect. 364 00:24:28,160 --> 00:24:29,520 That drink is coffee. 365 00:24:30,840 --> 00:24:34,720 Here in the UK, we get through 55 million cups each day. 366 00:24:42,360 --> 00:24:46,080 Part of the appeal is coffee's active ingredient, caffeine. 367 00:24:47,840 --> 00:24:51,640 And scientists are now close to understanding how caffeine boosts 368 00:24:51,640 --> 00:24:57,880 our reward pathway by studying, not humans but, surprisingly, bees. 369 00:25:01,520 --> 00:25:03,200 Alongside chocolate, 370 00:25:03,200 --> 00:25:05,840 Peru is also a major producer of coffee 371 00:25:05,840 --> 00:25:09,840 and I've come to see how this beautiful plant reproduces. 372 00:25:11,040 --> 00:25:14,840 In the wild the plant relies on insects for its pollination 373 00:25:14,840 --> 00:25:17,400 but therein lies a mystery. 374 00:25:17,400 --> 00:25:19,800 It seduces pollinating insects, 375 00:25:19,800 --> 00:25:23,160 looking for food, with the promise of nectar from flowers. 376 00:25:24,320 --> 00:25:28,320 But it also needs to defend itself from pests, so its cells secrete 377 00:25:28,320 --> 00:25:30,840 chemicals to keep other insects at bay. 378 00:25:32,080 --> 00:25:35,800 Plants can't run away and hide from their predators, 379 00:25:35,800 --> 00:25:39,560 so what they've done is developed a totally different 380 00:25:39,560 --> 00:25:42,920 evolutionary strategy - chemical weapons. 381 00:25:42,920 --> 00:25:45,400 So in the case of coffee, for example, 382 00:25:45,400 --> 00:25:51,440 you have these seeds here which are packed full of caffeine, 383 00:25:51,440 --> 00:25:54,440 which is toxic to insects in large doses. 384 00:25:54,440 --> 00:25:56,040 It's found in its leaves, 385 00:25:56,040 --> 00:25:58,640 it's found throughout the plant, but the weird thing is 386 00:25:58,640 --> 00:26:03,400 it's even found in flowers and the whole function of a flower 387 00:26:03,400 --> 00:26:07,280 is to attract insects, so it kind of begs the question 388 00:26:07,280 --> 00:26:09,280 if something else is going on here? 389 00:26:11,360 --> 00:26:15,160 Even though caffeine is toxic to insects in large doses, 390 00:26:15,160 --> 00:26:16,840 there must be something else about 391 00:26:16,840 --> 00:26:19,520 this chemical that insects find tempting. 392 00:26:21,720 --> 00:26:24,280 Understand this and it might help us understand 393 00:26:24,280 --> 00:26:26,520 why humans find coffee so tempting. 394 00:26:30,920 --> 00:26:34,520 Professor Geraldine Wright of Newcastle University is attempting 395 00:26:34,520 --> 00:26:38,720 to untangle this puzzle, with the help of her bees. 396 00:26:38,720 --> 00:26:42,360 Bees are one of the highest forms of life on the planet. 397 00:26:42,360 --> 00:26:45,760 They have evolved fairly sophisticated brains that allows 398 00:26:45,760 --> 00:26:48,320 them to learn floral traits and associate them with food. 399 00:26:49,560 --> 00:26:52,680 The bees are delicately harnessed to allow handling. 400 00:26:53,880 --> 00:26:56,720 They're then fed a sugar solution. 401 00:26:56,720 --> 00:26:58,560 Some will also be given caffeine 402 00:26:58,560 --> 00:27:01,440 to see whether this affects their behaviour. 403 00:27:01,440 --> 00:27:03,760 Coffee flowers produce a lot of scent. 404 00:27:03,760 --> 00:27:07,200 They have a beautiful floral scent that's like jasmine. 405 00:27:07,200 --> 00:27:09,000 And so in this experiment, 406 00:27:09,000 --> 00:27:12,960 we were training bees to learn to associate a floral scent 407 00:27:12,960 --> 00:27:14,680 with a food that contained caffeine. 408 00:27:20,760 --> 00:27:23,920 First, each bee is given a puff of the floral scent... 409 00:27:27,120 --> 00:27:29,560 ..immediately followed by a meal of sugar solution. 410 00:27:34,960 --> 00:27:38,520 Crucially, half the bees are also given caffeine 411 00:27:38,520 --> 00:27:39,920 and the other half none. 412 00:27:43,720 --> 00:27:46,040 The test comes 24 hours later. 413 00:27:48,320 --> 00:27:51,480 This time, the bees only get a puff of scent. 414 00:27:51,480 --> 00:27:53,360 Will they remember that yesterday, 415 00:27:53,360 --> 00:27:55,800 the same scent came along with a meal? 416 00:27:57,360 --> 00:28:00,200 First, Gerry tests the bees that haven't been given caffeine. 417 00:28:01,800 --> 00:28:05,480 If they remember the association between scent and food, 418 00:28:05,480 --> 00:28:09,200 they'll lift their mouthparts in anticipation of a rewarding meal. 419 00:28:12,840 --> 00:28:16,560 Just 20% respond to the scent but the majority do nothing. 420 00:28:22,760 --> 00:28:26,160 Next, the bees who'd had a caffeine fix with their food are tested. 421 00:28:30,520 --> 00:28:35,000 Incredibly, 60% of these bees respond to the scent alone. 422 00:28:36,640 --> 00:28:41,560 Three times as many bees who'd had caffeine remembered the association 423 00:28:41,560 --> 00:28:45,000 of scent and sugar reward a day later 424 00:28:45,000 --> 00:28:48,080 as compared to bees who had no caffeine. 425 00:28:48,080 --> 00:28:51,920 It's a result which helps begin to explain caffeine's power. 426 00:28:51,920 --> 00:28:56,480 A little dose of caffeine and nectar goes a long way to helping bees 427 00:28:56,480 --> 00:28:59,120 to learn and remember the scent of flowers. 428 00:29:00,120 --> 00:29:02,880 Caffeine itself is making the brain 429 00:29:02,880 --> 00:29:06,080 believe that these signals are more intense. 430 00:29:06,080 --> 00:29:09,240 Caffeine is amplifying the experience 431 00:29:09,240 --> 00:29:11,560 the bees have with sugar when 432 00:29:11,560 --> 00:29:14,360 they're eating and it's making it seem better. 433 00:29:14,360 --> 00:29:19,200 The results we found regarding bee memory can be translated to people. 434 00:29:19,200 --> 00:29:24,120 It's very likely that caffeine is affecting human memory in the same 435 00:29:24,120 --> 00:29:28,320 way, via the same mechanisms, basically by amplifying reward. 436 00:29:29,800 --> 00:29:33,240 So it begins to suggest that when we drink a coffee, 437 00:29:33,240 --> 00:29:36,600 that pleasant feeling of the hot liquid is just made even better by 438 00:29:36,600 --> 00:29:39,240 the caffeine, so we crave it again. 439 00:29:41,040 --> 00:29:45,400 And if you add sugar or syrup or cream to your coffee, 440 00:29:45,400 --> 00:29:48,960 then the caffeine will make this pleasure even more intense, 441 00:29:48,960 --> 00:29:51,520 so you're even more likely to go back for more. 442 00:29:53,800 --> 00:29:55,680 It could be that this is part of 443 00:29:55,680 --> 00:29:58,080 what makes our daily cup so addictive. 444 00:30:00,000 --> 00:30:03,960 Our brains learn to love the ritual of making or buying coffee. 445 00:30:05,960 --> 00:30:08,400 We're like bees, buzzing around flowers, 446 00:30:08,400 --> 00:30:11,960 seeking out that extra hit of pleasure each time we enjoy a cup. 447 00:30:23,520 --> 00:30:26,560 Our relationship with food is complex 448 00:30:26,560 --> 00:30:31,240 and the powerful human brain is very adaptable. 449 00:30:31,240 --> 00:30:35,880 That also means we can learn to love some rather unusual foods. 450 00:30:35,880 --> 00:30:38,720 We can acquire new tastes. 451 00:30:38,720 --> 00:30:43,640 Food that is delicious for some is revolting to others 452 00:30:43,640 --> 00:30:46,880 and that often depends on where you are in the world. 453 00:30:48,240 --> 00:30:50,160 For example, brain. 454 00:30:52,080 --> 00:30:57,160 Now as well as being a brain, this is also food, and here in Turkey, 455 00:30:57,160 --> 00:31:00,600 a sheep's brain salad is something of a delicacy. 456 00:31:00,600 --> 00:31:05,200 Now this brain is very small and that's because it comes from a sheep 457 00:31:05,200 --> 00:31:08,000 and sheep don't have to make lots of complex decisions. 458 00:31:08,000 --> 00:31:12,240 I like to think of sheep wandering the fields in the sunshine and 459 00:31:12,240 --> 00:31:14,720 occasionally they'll stop and have a bit of a nibble. 460 00:31:14,720 --> 00:31:16,320 When it comes to food, 461 00:31:16,320 --> 00:31:19,120 the thought process goes something along the lines of, 462 00:31:19,120 --> 00:31:21,680 "Grass, stop, eat." 463 00:31:25,360 --> 00:31:29,640 You can guarantee that while our sheep here might have enjoyed its 464 00:31:29,640 --> 00:31:33,480 meal of grass, it's never tried a cheesecake for pudding 465 00:31:33,480 --> 00:31:35,920 or a bit of horseradish on the side. 466 00:31:35,920 --> 00:31:39,480 And that's because its brain has a key difference to ours. 467 00:31:43,040 --> 00:31:46,160 If I cut this open, you can see that in some ways, 468 00:31:46,160 --> 00:31:50,400 it looks like a human brain, except that in a human this area here, 469 00:31:50,400 --> 00:31:53,760 which is called the frontal cortex, would be much, much bigger, 470 00:31:53,760 --> 00:31:56,800 and that's because it's where we make all our important 471 00:31:56,800 --> 00:32:00,200 conscious decisions like where am I going to go on holiday, 472 00:32:00,200 --> 00:32:04,080 do I really need that extra bit of chocolate cake? 473 00:32:04,080 --> 00:32:08,080 The frontal cortex is in many ways the area of the brain that makes our 474 00:32:08,080 --> 00:32:11,800 lives so much more rich and complex than that of a sheep. 475 00:32:15,960 --> 00:32:20,480 It's our enlarged cortex that has led us to experiment with our food, 476 00:32:20,480 --> 00:32:25,240 inventing numerous delicacies across cultures and cuisines. 477 00:32:26,880 --> 00:32:29,240 And that's where it gets a little bit tricky. 478 00:32:29,240 --> 00:32:33,680 I've never eaten a brain before but there's always a first time for 479 00:32:33,680 --> 00:32:40,360 everything, so some lemon juice, a little bit of olive oil... 480 00:32:44,920 --> 00:32:46,880 ..and here goes. 481 00:32:54,120 --> 00:32:56,280 Mmm, yum! 482 00:32:57,520 --> 00:32:59,400 Aw, God. 483 00:32:59,400 --> 00:33:02,320 Not at all what I expected. 484 00:33:02,320 --> 00:33:04,360 I was expecting something a little bit 485 00:33:04,360 --> 00:33:08,320 rubbery and this is actually more like a sort of strange jelly. 486 00:33:10,120 --> 00:33:13,520 And not a lovely aftertaste. 487 00:33:15,520 --> 00:33:19,640 I think this is an acquired taste and it's not one I plan to acquire. 488 00:33:25,840 --> 00:33:29,840 Acquiring taste is something we excel at. 489 00:33:29,840 --> 00:33:34,280 It seems that our brains are wired to enjoy the novelty in our food 490 00:33:34,280 --> 00:33:37,840 and that we can learn to overcome disgust. 491 00:33:37,840 --> 00:33:42,360 Sometimes, in the case of chilli peppers, even pain. 492 00:33:54,000 --> 00:33:57,880 To investigate the powerful effect that chilli peppers have on the body 493 00:33:57,880 --> 00:34:02,520 and brain, I've come to the largest market on the planet 494 00:34:02,520 --> 00:34:05,640 where tonnes of chillies are sold every day. 495 00:34:09,160 --> 00:34:11,600 I'm in Mexico, where humans first learned 496 00:34:11,600 --> 00:34:14,560 to farm the chilli plant some 6,000 years ago. 497 00:34:19,840 --> 00:34:22,160 The spicy flavour in chillies is 498 00:34:22,160 --> 00:34:25,240 caused by this chemical called capsaicin. 499 00:34:25,240 --> 00:34:29,480 I say flavour, but it's really like more of a texture, 500 00:34:29,480 --> 00:34:31,840 almost a feeling and this is where it all is, 501 00:34:31,840 --> 00:34:34,960 so everyone says it's the seeds that are spicy and that's not true. 502 00:34:34,960 --> 00:34:36,440 It's this business here, 503 00:34:36,440 --> 00:34:40,040 this white spongy layer that we call the placenta. 504 00:34:40,040 --> 00:34:45,680 It's that bit and that's where pretty much all your capsaicin is manufactured. 505 00:34:45,680 --> 00:34:49,240 These tiny little dots along there. 506 00:34:49,240 --> 00:34:52,240 Each one of those is a gland that produces capsaicin. 507 00:34:54,080 --> 00:34:58,960 And all this capsaicin has a very direct effect on a particular part 508 00:34:58,960 --> 00:35:00,800 of our biology... 509 00:35:06,720 --> 00:35:09,280 Something known as the TRPV1 receptor. 510 00:35:12,920 --> 00:35:15,520 TRPV1 receptors are found in the mouth, 511 00:35:15,520 --> 00:35:18,520 on the tongue and throughout the body. 512 00:35:18,520 --> 00:35:23,440 Their purpose is to detect the sensation of scalding heat and raise 513 00:35:23,440 --> 00:35:26,640 an alarm signal in the brain to protect the body from harm. 514 00:35:32,760 --> 00:35:34,080 Purely by chance, 515 00:35:34,080 --> 00:35:37,440 the shape of the capsaicin molecule happens to fit onto 516 00:35:37,440 --> 00:35:41,000 the TRPV1 receptor like a master key in a lock. 517 00:35:42,680 --> 00:35:45,640 This triggers the receptors to activate, 518 00:35:45,640 --> 00:35:48,000 and they send a signal to the brain, 519 00:35:48,000 --> 00:35:51,160 fooling it into thinking that the mouth is on fire. 520 00:35:55,800 --> 00:35:58,800 Capsaicin has an almost unrivalled ability 521 00:35:58,800 --> 00:36:00,600 to generate pain in our bodies. 522 00:36:03,400 --> 00:36:05,560 So how did a potential food source 523 00:36:05,560 --> 00:36:08,880 end up with this astonishingly powerful irritant? 524 00:36:10,640 --> 00:36:13,680 To answer the question, I'm going to need the help of a hopefully 525 00:36:13,680 --> 00:36:16,960 - friendly parrot. - You look scared, James. 526 00:36:16,960 --> 00:36:20,920 - I am very scared. - Try not to be. You might get a bit closer. 527 00:36:20,920 --> 00:36:22,520 Whoa! 528 00:36:22,520 --> 00:36:25,320 No, I don't want to do this! 529 00:36:25,320 --> 00:36:26,880 I'm going to give it to you there. 530 00:36:26,880 --> 00:36:28,800 - Jesus. - It's cos you're snatching it away. 531 00:36:28,800 --> 00:36:31,480 I know, I know. Oh, and he nearly got me. 532 00:36:33,120 --> 00:36:35,600 OK. There you go. 533 00:36:35,600 --> 00:36:38,440 Have a look at that. OK. 534 00:36:38,440 --> 00:36:40,320 What do you think? 535 00:36:40,320 --> 00:36:43,560 You like that, don't you? Yeah? 536 00:36:43,560 --> 00:36:47,760 In the wild, it's relatives of these guys, birds, 537 00:36:47,760 --> 00:36:50,240 that are the key way that chilli plants disburse their seeds 538 00:36:50,240 --> 00:36:52,400 everywhere and that's because birds 539 00:36:52,400 --> 00:36:55,000 are completely immune to the effect of capsaicin. 540 00:36:55,000 --> 00:36:57,600 It's like it doesn't even exist for them. 541 00:36:57,600 --> 00:36:59,600 Birds do have a TRPV1 receptor, 542 00:36:59,600 --> 00:37:02,720 but is a different shape, so no lock and key fit, 543 00:37:02,720 --> 00:37:05,880 no activation and no feeling whatsoever. 544 00:37:07,640 --> 00:37:10,240 So the chillies get their seeds spread on the wing 545 00:37:10,240 --> 00:37:12,680 whilst being left alone by other animals. 546 00:37:15,040 --> 00:37:18,600 But then came along an ape with a giant frontal cortex 547 00:37:18,600 --> 00:37:20,640 that learned to love the burn. 548 00:37:27,320 --> 00:37:31,160 Michael and I have come to a food and music festival here in Bristol... 549 00:37:33,240 --> 00:37:36,080 ..where we're going to compete in a chilli-eating contest. 550 00:37:40,080 --> 00:37:42,880 We're taking on ten other brave souls... 551 00:37:45,600 --> 00:37:49,600 ..including a man dressed as a chilli and another dressed as a zombie... 552 00:37:49,600 --> 00:37:52,480 - COMMENTATOR: - Good afternoon, Bristol! 553 00:37:52,480 --> 00:37:55,600 ..to experience first-hand the effect that chillies have on our 554 00:37:55,600 --> 00:37:57,840 bodies and our brains. 555 00:37:57,840 --> 00:38:00,880 Welcome to our cathedral of pain and chaos. 556 00:38:00,880 --> 00:38:03,400 I'm actually feeling slightly nervous. 557 00:38:03,400 --> 00:38:07,120 I do quite like hot things and although this is not really 558 00:38:07,120 --> 00:38:11,240 a competition, it is. I'd quite like to do better than you. 559 00:38:11,240 --> 00:38:14,160 I grew up eating chillies. I've been using them since I was 560 00:38:14,160 --> 00:38:16,160 eight years old, but famous last words. 561 00:38:16,160 --> 00:38:18,760 OK, there's a good chance you'll beat me, then. 562 00:38:18,760 --> 00:38:24,000 Bristol, please give a big round of applause to all the chilli contestants. 563 00:38:24,000 --> 00:38:25,400 CHEERING AND APPLAUSE 564 00:38:25,400 --> 00:38:28,080 The things we do in the name of science. 565 00:38:28,080 --> 00:38:29,880 Good to go. Good luck. 566 00:38:29,880 --> 00:38:33,960 The principle of the competition is simple, at each round, 567 00:38:33,960 --> 00:38:37,200 the chillies will get hotter and hotter and the person 568 00:38:37,200 --> 00:38:39,000 who lasts the longest wins. 569 00:38:39,000 --> 00:38:43,720 Some very brave, stupid people. 570 00:38:46,280 --> 00:38:48,600 This is the first chilli that they're going to get. 571 00:38:48,600 --> 00:38:50,680 It is called a Dutch long chilli. 572 00:38:53,080 --> 00:38:56,160 On my mark, three, two, one. 573 00:38:56,160 --> 00:38:58,840 Eat! 574 00:38:58,840 --> 00:39:03,040 The ferocity of a chilli pepper is measured in Scoville heat units. 575 00:39:03,040 --> 00:39:06,120 This weighs in at 500 Scoville units. 576 00:39:06,120 --> 00:39:07,840 The higher the Scoville number, 577 00:39:07,840 --> 00:39:11,920 the more capsaicin in the chilli and more fiery in that becomes. 578 00:39:11,920 --> 00:39:14,480 It's got a bit of bite to it. 579 00:39:14,480 --> 00:39:18,800 There's a long way to go before we encounter the most ferocious chillies 580 00:39:18,800 --> 00:39:22,440 that can reach millions of Scovilles. 581 00:39:22,440 --> 00:39:23,480 So this is OK. 582 00:39:25,880 --> 00:39:28,720 On my mark, three, two, one. 583 00:39:28,720 --> 00:39:31,080 Eat! 584 00:39:31,080 --> 00:39:33,280 These are chunky. 585 00:39:33,280 --> 00:39:35,400 These have got a lot of moisture in, actually. 586 00:39:35,400 --> 00:39:37,520 Savour it and enjoy them. 587 00:39:39,200 --> 00:39:42,040 Three, two, one, eat! 588 00:39:44,080 --> 00:39:46,280 That one went up the nose! 589 00:39:46,280 --> 00:39:47,520 Oh! 590 00:39:49,080 --> 00:39:51,720 Please give these guys a round of applause. 591 00:39:54,320 --> 00:39:57,600 We've now consumed a considerable amount of capsaicin. 592 00:39:57,600 --> 00:40:02,520 And all those capsaicin molecules are attaching themselves to TRPV1 593 00:40:02,520 --> 00:40:04,200 receptors in our mouths... 594 00:40:04,200 --> 00:40:05,600 Go on, get it down you. 595 00:40:05,600 --> 00:40:10,160 ..sending signals to our brains, making us think we are literally on fire. 596 00:40:11,400 --> 00:40:13,920 My eyes are already beginning to water 597 00:40:13,920 --> 00:40:16,000 and my pulse is shooting up. 598 00:40:16,000 --> 00:40:19,200 This is the fight or flight response. 599 00:40:19,200 --> 00:40:22,440 The fight or flight response normally occurs 600 00:40:22,440 --> 00:40:24,800 when we sense a threat or danger. 601 00:40:28,200 --> 00:40:31,200 The body responds with a shot of adrenaline. 602 00:40:32,960 --> 00:40:35,720 The heart beats harder and faster. 603 00:40:36,720 --> 00:40:38,680 Pupils dilate. 604 00:40:38,680 --> 00:40:41,120 You breathe deeper. 605 00:40:41,120 --> 00:40:43,320 And your arteries widen, 606 00:40:43,320 --> 00:40:47,520 sending a flood of blood to your muscles to get them ready for action. 607 00:40:47,520 --> 00:40:51,480 It's all accompanied by a rather more positive feeling that might 608 00:40:51,480 --> 00:40:55,280 hold the key to why some people like this fiery sensation. 609 00:40:56,920 --> 00:41:00,200 The thing is that when you eat a really, really hot chilli, 610 00:41:00,200 --> 00:41:06,080 you also get an endorphin response which is one of the most natural 611 00:41:06,080 --> 00:41:09,240 opiates. Sometimes you get it when you do exercise. But it's supposed 612 00:41:09,240 --> 00:41:12,320 to be a feel-good hormone. I'm not sure I've got that yet. 613 00:41:14,520 --> 00:41:17,120 It's part of the chilli's allure. 614 00:41:17,120 --> 00:41:19,440 Endorphins are powerful painkillers, 615 00:41:19,440 --> 00:41:24,800 released by own bodies and so should lessen the chilli's sting. 616 00:41:24,800 --> 00:41:28,720 But they're also thought to induce a pervasive sense of happiness, 617 00:41:28,720 --> 00:41:31,200 even a rush, which can be addictive. 618 00:41:31,200 --> 00:41:33,240 Yes! Nicely done. 619 00:41:35,040 --> 00:41:36,840 Three, two, one. 620 00:41:36,840 --> 00:41:38,920 Eat! 621 00:41:40,840 --> 00:41:42,920 How are you doing? 622 00:41:42,920 --> 00:41:44,440 HE GROANS 623 00:41:46,880 --> 00:41:51,440 Our fifth chilli is 15,000 Scovilles. 624 00:41:51,440 --> 00:41:54,240 With our brain's pain centres in overdrive, 625 00:41:54,240 --> 00:41:56,960 Michael and I need to dig deep to stay in the contest. 626 00:42:00,240 --> 00:42:01,840 Oh, dear. 627 00:42:04,240 --> 00:42:06,280 See you! 628 00:42:08,680 --> 00:42:10,480 I can feel basically 629 00:42:10,480 --> 00:42:13,960 the tears coming out, the snot is coming out 630 00:42:13,960 --> 00:42:16,360 and I thought I was going to vomit for a moment there, 631 00:42:16,360 --> 00:42:19,280 so I thought it's probably a good time to withdraw. 632 00:42:19,280 --> 00:42:24,000 Ladies and gentlemen, please give Mr Michael Mosley a round of applause. 633 00:42:24,000 --> 00:42:29,520 The best thing to soothe the burn is not water, but milk. 634 00:42:29,520 --> 00:42:31,680 It helps neutralise capsaicin 635 00:42:31,680 --> 00:42:34,760 because it contains something like casein. 636 00:42:37,400 --> 00:42:41,080 Casein molecules are attracted to oily substances 637 00:42:41,080 --> 00:42:43,520 like the capsaicin in chillies. 638 00:42:43,520 --> 00:42:45,960 They surround the capsaicin, 639 00:42:45,960 --> 00:42:51,200 preventing it from latching on to the TRPV1 receptors in our bodies 640 00:42:51,200 --> 00:42:53,440 and it just gets washed away. 641 00:42:53,440 --> 00:42:56,720 So if you ever encounter curry you can't handle, 642 00:42:56,720 --> 00:42:59,880 don't bother with water, reach for the dairy. 643 00:42:59,880 --> 00:43:03,800 Three, two, one, eat! 644 00:43:06,560 --> 00:43:09,440 I'm still in the running, and on to the sixth chilli. 645 00:43:11,440 --> 00:43:15,160 And this one is 30,000 Scovilles. 646 00:43:15,160 --> 00:43:17,320 60 times hotter than the first. 647 00:43:20,520 --> 00:43:23,960 The reason why psychologists think we like eating chillies 648 00:43:23,960 --> 00:43:27,520 is there's a minor form of sadomasochism, 649 00:43:27,520 --> 00:43:30,440 a bit like riding a roller-coaster. 650 00:43:30,440 --> 00:43:32,520 And I can confirm that. 651 00:43:32,520 --> 00:43:36,640 Driven by the human rush of excitement. 652 00:43:38,880 --> 00:43:43,120 It's thrill-seeking, feeding our brain's desire for stimulation. 653 00:43:43,120 --> 00:43:44,440 Honestly. 654 00:43:44,440 --> 00:43:47,840 Ladies and gentlemen, please give James Wong a round of applause. 655 00:43:50,840 --> 00:43:53,080 Excellent work. 656 00:43:53,080 --> 00:43:55,760 Oh, that milk is good. 657 00:43:55,760 --> 00:43:57,200 I can still taste it. 658 00:43:57,200 --> 00:44:01,480 We still don't know why people have different tolerances to fiery foods 659 00:44:01,480 --> 00:44:05,400 but we can speculate that people with thrill-seeking personalities 660 00:44:05,400 --> 00:44:08,360 are more likely to expose themselves to the burn 661 00:44:08,360 --> 00:44:10,800 and may build up a tolerance to capsaicin. 662 00:44:12,880 --> 00:44:16,240 Out of 12 people, we finished 11th and 12th. 663 00:44:16,240 --> 00:44:19,280 And the rest are soon dropping like flies. 664 00:44:19,280 --> 00:44:23,240 Right, so next up, we have Thai red chillies. 665 00:44:23,240 --> 00:44:26,920 Three, two, one, eat! 666 00:44:26,920 --> 00:44:31,200 Oh, my goodness me. 667 00:44:31,200 --> 00:44:33,280 These are naughty. 668 00:44:33,280 --> 00:44:35,240 Jerry's gone. 669 00:44:37,680 --> 00:44:41,840 The last two contestants have overcome intense pain 670 00:44:41,840 --> 00:44:44,440 to reach the penultimate round. 671 00:44:49,200 --> 00:44:52,880 They now face the infamous Jay's Red Ghost Chilli, 672 00:44:52,880 --> 00:44:57,000 at a staggering 1.2 million Scovilles. 673 00:45:00,680 --> 00:45:04,240 Too much for Steve. Drinking milk puts him out of the competition. 674 00:45:04,240 --> 00:45:06,440 Rebecca has won. 675 00:45:24,440 --> 00:45:29,680 Our love of chillies shows an experimental side to our eating habits. 676 00:45:29,680 --> 00:45:32,760 Rewarded by endorphins and a rush of pleasure, 677 00:45:32,760 --> 00:45:35,280 we've become culinary adventurers, 678 00:45:35,280 --> 00:45:38,480 constantly seeking out novel food experiences. 679 00:45:42,400 --> 00:45:45,800 It's even led us to consume a chemical that, 680 00:45:45,800 --> 00:45:48,960 in its pure form, is frankly poisonous. 681 00:45:48,960 --> 00:45:52,400 It comes in many guises. 682 00:45:52,400 --> 00:45:56,360 It can pass right through the barrier which is supposed to protect 683 00:45:56,360 --> 00:45:59,480 our brains and directly interfere with them. 684 00:45:59,480 --> 00:46:01,760 It is, of course, alcohol. 685 00:46:04,720 --> 00:46:07,000 This is red wine. 686 00:46:07,000 --> 00:46:10,880 It smells rather nice, and I'm sure it's the product of years of hard 687 00:46:10,880 --> 00:46:13,760 work and experience, but I'm not going to drink it. 688 00:46:13,760 --> 00:46:16,600 I'm going to send it off to be evaporated. 689 00:46:20,080 --> 00:46:23,440 Alcohol has a lower boiling point than water. 690 00:46:23,440 --> 00:46:27,200 So, gently heating the wine in a rotary evaporator turns it into 691 00:46:27,200 --> 00:46:31,320 a vapour, which rises and can be collected. 692 00:46:31,320 --> 00:46:34,720 Alcohol is packed with energy. 693 00:46:34,720 --> 00:46:37,080 Here it is. 694 00:46:37,080 --> 00:46:39,400 Back again, smelling completely different. 695 00:46:39,400 --> 00:46:44,840 And by now, it should be almost pure alcohol. 696 00:46:44,840 --> 00:46:49,200 And if we dim the lights down, we should be able to see it burn. 697 00:46:52,320 --> 00:46:55,800 Every gram releases seven calories of energy, 698 00:46:55,800 --> 00:46:58,360 so drinking adds calories to your diet. 699 00:47:00,960 --> 00:47:03,800 But energy is not why most of us drink. 700 00:47:06,000 --> 00:47:10,280 Alcohol's popularity arises from what it does to our brains... 701 00:47:12,160 --> 00:47:16,280 ..which means pretty well every culture has invented its own tipple. 702 00:47:26,400 --> 00:47:29,560 To show just how widely alcohol is enjoyed, 703 00:47:29,560 --> 00:47:33,320 I've come to somewhere where they produce an extraordinary brew. 704 00:47:36,640 --> 00:47:41,080 It's in northern Peru, and here the locals have improvised a unique way 705 00:47:41,080 --> 00:47:44,240 to produce their own steady stream of alcohol. 706 00:47:48,240 --> 00:47:50,240 These are the Chanka people, 707 00:47:50,240 --> 00:47:54,760 they have been here as a group for over 700 years and, way back, 708 00:47:54,760 --> 00:47:56,480 had the Inca for an enemy. 709 00:47:58,040 --> 00:48:02,440 And throughout their history, they've made a drink called masato. 710 00:48:02,440 --> 00:48:07,000 Like all cultures they use what's to hand, and for them 711 00:48:07,000 --> 00:48:09,240 that's the root of the yucca plant. 712 00:48:09,240 --> 00:48:11,120 Hi there. 713 00:48:11,120 --> 00:48:12,760 Hello. 714 00:48:12,760 --> 00:48:14,440 THEY TALK IN OWN LANGUAGE 715 00:48:14,440 --> 00:48:16,080 Hi there. 716 00:48:16,080 --> 00:48:20,080 I've joined them to reveal the lengths to which people will go to 717 00:48:20,080 --> 00:48:22,040 in search of their own tipple. 718 00:48:23,200 --> 00:48:25,520 Once the yucca roots are peeled, 719 00:48:25,520 --> 00:48:28,720 they are boiled to soften them and then they are crushed. 720 00:48:28,720 --> 00:48:31,200 THEY LAUGH 721 00:48:31,200 --> 00:48:34,440 They are having a good laugh, I'm not entirely sure what it's about. 722 00:48:34,440 --> 00:48:37,800 All yours. I'm hoping I'll be better at the next bit... 723 00:48:39,240 --> 00:48:42,400 ..when they add a crucial ingredient... 724 00:48:44,800 --> 00:48:46,640 ..spit. 725 00:48:48,320 --> 00:48:50,080 More. 726 00:48:50,080 --> 00:48:51,640 More! 727 00:48:55,080 --> 00:48:56,560 THEY LAUGH 728 00:48:58,240 --> 00:49:00,120 Yes, that's how it's done. 729 00:49:05,880 --> 00:49:08,560 Apparently, this is normally just a female only activity. 730 00:49:08,560 --> 00:49:10,080 I'm not sure 731 00:49:10,080 --> 00:49:14,400 adding a bit of sort of Gringo male spit to it is adding to the flavour. 732 00:49:15,920 --> 00:49:19,480 This may look absolutely disgusting but it's actually part of the process 733 00:49:19,480 --> 00:49:24,160 because the saliva is actually an intrinsic part of the whole thing. 734 00:49:24,160 --> 00:49:26,160 What happens is the saliva 735 00:49:26,160 --> 00:49:28,600 in your mouth contains an enzyme called amylase 736 00:49:28,600 --> 00:49:30,720 and this stuff is all starch. 737 00:49:30,720 --> 00:49:33,400 What the amylase does is it breaks down the starch and releases 738 00:49:33,400 --> 00:49:35,080 the sugars inside it. 739 00:49:35,080 --> 00:49:38,480 If you've ever stuck a cracker in your mouth and left it there 740 00:49:38,480 --> 00:49:41,560 or perhaps you've stuck some white bread in your mouth and left it 741 00:49:41,560 --> 00:49:43,640 there, what you'll notice over a little while is 742 00:49:43,640 --> 00:49:45,080 it starts to taste rather sweet, 743 00:49:45,080 --> 00:49:48,400 and that's because the amylase in your mouth is breaking down starches 744 00:49:48,400 --> 00:49:51,120 and releasing sugar. So you have to 745 00:49:51,120 --> 00:49:55,640 stick it in, run it round, amylase springs into action. 746 00:49:55,640 --> 00:49:57,720 And then, 747 00:49:57,720 --> 00:49:59,800 you gob it out. 748 00:50:03,040 --> 00:50:04,960 The point is to get some sugar. 749 00:50:07,200 --> 00:50:08,560 Once you have sugar, 750 00:50:08,560 --> 00:50:12,040 all you need to turn it into alcohol is a little fresh air. 751 00:50:15,320 --> 00:50:18,360 That's because our atmosphere contains many forms of tiny 752 00:50:18,360 --> 00:50:21,680 single-celled microorganisms called yeast. 753 00:50:24,760 --> 00:50:28,320 When one of these yeast cells lands on the chewed yucca, 754 00:50:28,320 --> 00:50:31,840 it starts to feed on the sugar and begins to multiply. 755 00:50:38,920 --> 00:50:42,120 And they get the energy to do this from the breakdown of sugar. 756 00:50:44,120 --> 00:50:47,760 The yeast starts digesting the sugars in the yucca. 757 00:50:47,760 --> 00:50:51,800 In the process, each sugar molecule is converted into four smaller 758 00:50:51,800 --> 00:50:57,000 molecules, two of carbon dioxide and two of alcohol, as waste. 759 00:51:02,680 --> 00:51:05,480 The small size of the alcohol molecule 760 00:51:05,480 --> 00:51:07,600 is crucial to our enjoyment. 761 00:51:07,600 --> 00:51:11,040 Being small helps it pass through the barrier around the brain's blood 762 00:51:11,040 --> 00:51:14,120 vessels and go straight into the brain itself. 763 00:51:15,600 --> 00:51:19,000 Now, fermentation is at the heart of lots of the things we love. 764 00:51:19,000 --> 00:51:23,880 Not just booze, but chocolate, yoghurt, and of course, bread. 765 00:51:23,880 --> 00:51:27,840 Now, with bread, the product of fermentation that you really want is 766 00:51:27,840 --> 00:51:30,560 not the alcohol but the carbon dioxide. 767 00:51:30,560 --> 00:51:32,920 Because that's what makes it rise 768 00:51:32,920 --> 00:51:35,880 and produces that lovely spongy texture. 769 00:51:35,880 --> 00:51:38,960 There is a small amount of alcohol in the dough, but that gets 770 00:51:38,960 --> 00:51:42,040 evaporated off when the bread is baked. 771 00:51:43,720 --> 00:51:48,520 Yet in masato, it's all about the alcohol and it's beginning to build. 772 00:51:51,960 --> 00:51:54,280 But there's a limit to how strong it can become. 773 00:51:56,160 --> 00:51:59,760 Once the alcohol level increases to around 6%, 774 00:51:59,760 --> 00:52:04,680 it becomes concentrated enough to poison many types of yeast, which die. 775 00:52:04,680 --> 00:52:08,280 And that in turn slows the fermentation process. 776 00:52:10,720 --> 00:52:14,040 And it's at this point it's ready to enjoy. 777 00:52:19,240 --> 00:52:22,840 It's my last night and the villagers have invited me to eat with them. 778 00:52:25,440 --> 00:52:27,840 So, with some trepidation, 779 00:52:27,840 --> 00:52:31,480 I'm going to sample their unique form of yucca beer. 780 00:52:41,920 --> 00:52:44,120 Right, OK. 781 00:52:44,120 --> 00:52:47,000 So, moment of truth. I'm a little apprehensive. 782 00:52:51,240 --> 00:52:54,720 Hm. It wasn't what I was expecting. 783 00:52:54,720 --> 00:52:57,960 It's kind of got a bit of an alcoholic kick to it, 784 00:52:57,960 --> 00:53:00,120 and it's quite bitter. 785 00:53:00,120 --> 00:53:01,880 It's almost sort of yoghurty. 786 00:53:08,880 --> 00:53:11,880 THEY SPEAK IN SPANISH 787 00:53:12,880 --> 00:53:15,200 OK. You drink it pretty well every day, do you? 788 00:53:15,200 --> 00:53:16,720 Todos los dias. 789 00:53:16,720 --> 00:53:22,080 Muchas gracias. En ingles, decimos, "cheers". 790 00:53:22,080 --> 00:53:23,920 Cheers? Cheers. 791 00:53:23,920 --> 00:53:25,800 - Salud? - "Salud", exactly. 792 00:53:29,120 --> 00:53:30,880 It's not terribly alcoholic. 793 00:53:30,880 --> 00:53:34,440 I'd guess it's probably about 4% or 5%. 794 00:53:34,440 --> 00:53:37,440 But I suspect if you drink enough of it, you get fairly jolly. 795 00:53:51,800 --> 00:53:56,080 After a few bowls, I'm starting to feel the effects. 796 00:53:56,080 --> 00:53:58,320 When it gets into your bloodstream, 797 00:53:58,320 --> 00:54:03,280 it hits your brain and there it really starts to do the business 798 00:54:03,280 --> 00:54:06,000 because one of the things it does is it affects 799 00:54:06,000 --> 00:54:09,760 a neurotransmitter called GABA and it actually... 800 00:54:09,760 --> 00:54:11,880 I'm sorry, I'm slightly losing... 801 00:54:11,880 --> 00:54:14,040 I'm losing the thread here. 802 00:54:18,320 --> 00:54:22,640 What I'm trying to say is that GABA is a neurotransmitter or 803 00:54:22,640 --> 00:54:25,600 chemical messenger that is present throughout the brain. 804 00:54:28,000 --> 00:54:30,840 Normally, it regulates the brain's activity. 805 00:54:30,840 --> 00:54:34,760 It's function is to act rather like a brake on brain cells, 806 00:54:34,760 --> 00:54:38,200 stopping them firing at the wrong time. 807 00:54:39,400 --> 00:54:42,240 You've got the GABA neurotransmitters 808 00:54:42,240 --> 00:54:44,760 and what happens is the alcohol... 809 00:54:46,840 --> 00:54:49,880 Alcohol interferes with the GABA system... 810 00:54:51,840 --> 00:54:56,360 ..by making brain cells more receptive to GABA. 811 00:54:56,360 --> 00:55:00,920 The potency of GABA increases and so does the dampening effect 812 00:55:00,920 --> 00:55:03,680 on the brain, switching off areas one by one. 813 00:55:06,560 --> 00:55:11,440 At first, this can make you feel liberated, excited, amusing, 814 00:55:11,440 --> 00:55:14,320 because the alcohol starts by switching off 815 00:55:14,320 --> 00:55:16,680 the areas that control our inhibitions. 816 00:55:16,680 --> 00:55:19,120 Yep. Life and soul. 817 00:55:19,120 --> 00:55:24,000 These regions have brain cells with the greatest number of GABA receptors, 818 00:55:24,000 --> 00:55:27,480 so they are most sensitive to the effects of alcohol. 819 00:55:27,480 --> 00:55:32,200 The emotional regions of the brain are the next to be suppressed. 820 00:55:32,200 --> 00:55:35,360 They have almost as many GABA receptors. 821 00:55:35,360 --> 00:55:40,080 They are followed by your motor controlled region, and then memory. 822 00:55:40,080 --> 00:55:43,720 What GABA does normally is it switches off parts of your brain, 823 00:55:43,720 --> 00:55:46,960 I think it's that, but I've slightly forgotten... 824 00:55:46,960 --> 00:55:48,880 Finally, if you are blind drunk, 825 00:55:48,880 --> 00:55:50,720 you are left with only 826 00:55:50,720 --> 00:55:53,400 the most basic parts of your brain still operating. 827 00:55:53,400 --> 00:55:57,120 They have the least GABA receptors and fortunately, 828 00:55:57,120 --> 00:56:01,240 they go on keeping you breathing and your heartbeat ticking over, 829 00:56:01,240 --> 00:56:03,800 even when you're unconscious. 830 00:56:03,800 --> 00:56:07,040 Thankfully, I am not at that stage tonight. 831 00:56:09,960 --> 00:56:12,960 Alcohol has a dramatic and in many ways 832 00:56:12,960 --> 00:56:15,960 a very addictive effect on our brains. 833 00:56:17,200 --> 00:56:21,680 It is so addictive and pleasurable that humans will find just about 834 00:56:21,680 --> 00:56:23,720 any way they can to make it, 835 00:56:23,720 --> 00:56:27,920 even if all you have to start with is some yucca. 836 00:56:30,960 --> 00:56:33,000 THEY SING 837 00:56:35,320 --> 00:56:38,800 'The deep connection between our food and brain...' 838 00:56:38,800 --> 00:56:40,360 Whoa! 839 00:56:40,360 --> 00:56:41,920 '..is there for a reason...' 840 00:56:41,920 --> 00:56:43,240 That's intense. 841 00:56:43,240 --> 00:56:46,200 'It's part of our evolutionary story.' 842 00:56:49,520 --> 00:56:51,240 We indulge our senses, 843 00:56:51,240 --> 00:56:54,760 which, in turn, reward us with feelings of pleasure in our minds... 844 00:56:58,360 --> 00:57:01,560 ..keeping us coming back to the table for more. 845 00:57:08,000 --> 00:57:09,840 Meanwhile, across the world, 846 00:57:09,840 --> 00:57:13,280 food scientists will continue to delve into the chemistry, 847 00:57:13,280 --> 00:57:19,120 physics and biology of our food, to try and understand how it works 848 00:57:19,120 --> 00:57:21,680 on our bodies and on our minds. 849 00:57:21,680 --> 00:57:26,280 And, all the while, our love affair with food continues to evolve. 850 00:57:26,280 --> 00:57:30,560 And that's because we are constantly pushing the barriers, 851 00:57:30,560 --> 00:57:33,080 looking for new ways to stimulate 852 00:57:33,080 --> 00:57:36,240 our incredibly demanding human brains. 853 00:57:40,040 --> 00:57:44,320 How does science change your view about what we eat? 854 00:57:44,320 --> 00:57:48,720 Test your food instincts and find out more facts about food by going 855 00:57:48,720 --> 00:57:51,080 to the website on the screen 856 00:57:51,080 --> 00:57:53,480 and follow the links to the Open University.