WEBVTT 00:00:00.478 --> 00:00:02.213 Three and a half years ago, 00:00:02.213 --> 00:00:05.463 I made one of the best decisions of my life. 00:00:05.463 --> 00:00:07.526 As my New Year's resolution, 00:00:07.526 --> 00:00:11.765 I gave up dieting, stopped worrying about my weight, 00:00:11.765 --> 00:00:14.790 and learned to eat mindfully. 00:00:14.790 --> 00:00:18.673 Now I eat whenever I'm hungry, 00:00:18.673 --> 00:00:21.736 and I've lost 10 pounds. NOTE Paragraph 00:00:21.736 --> 00:00:24.273 This was me at age 13, 00:00:24.273 --> 00:00:26.813 when I started my first diet. 00:00:26.813 --> 00:00:29.825 I look at that picture now, and I think, 00:00:29.825 --> 00:00:31.659 you did not need a diet, 00:00:31.659 --> 00:00:34.330 you needed a fashion consult. 00:00:34.330 --> 00:00:36.737 (Laughter) 00:00:36.737 --> 00:00:39.806 But I thought I needed to lose weight, 00:00:39.806 --> 00:00:41.268 and when I gained it back, 00:00:41.268 --> 00:00:45.196 of course I blamed myself. 00:00:45.196 --> 00:00:47.703 And for the next three decades, 00:00:47.703 --> 00:00:50.458 I was on and off various diets. 00:00:50.458 --> 00:00:52.530 No matter what I tried, 00:00:52.530 --> 00:00:55.361 the weight I'd lost always came back. 00:00:55.361 --> 00:00:58.962 I'm sure many of you know the feeling. NOTE Paragraph 00:00:58.962 --> 00:01:00.523 As a neuroscientist, 00:01:00.523 --> 00:01:03.337 I wondered, why is this so hard? 00:01:03.337 --> 00:01:05.897 Obviously, how much you weigh depends on 00:01:05.897 --> 00:01:08.487 how much you eat and how much energy you burn. 00:01:08.487 --> 00:01:10.703 What most people don't realize 00:01:10.703 --> 00:01:12.516 is that hunger and energy use 00:01:12.516 --> 00:01:14.620 are controlled by the brain, 00:01:14.620 --> 00:01:18.135 mostly without your awareness. 00:01:18.135 --> 00:01:21.695 Your brain does a lot of its work behind the scenes, 00:01:21.695 --> 00:01:23.911 and that is a good thing, 00:01:23.911 --> 00:01:26.097 because your conscious mind -- 00:01:26.097 --> 00:01:27.964 how do we put this politely? -- 00:01:27.964 --> 00:01:31.239 it's easily distracted. 00:01:31.239 --> 00:01:33.944 It's good that you don't have to remember to breathe 00:01:33.944 --> 00:01:36.584 when you get caught up in a movie. 00:01:36.584 --> 00:01:38.601 You don't forget how to walk 00:01:38.601 --> 00:01:41.516 because you're thinking about what to have for dinner. NOTE Paragraph 00:01:41.516 --> 00:01:43.500 Your brain also has its own sense 00:01:43.500 --> 00:01:45.265 of what you should weigh, 00:01:45.265 --> 00:01:48.327 no matter what you consciously believe. 00:01:48.327 --> 00:01:50.367 This is called your set point, 00:01:50.367 --> 00:01:52.033 but that's a misleading term, 00:01:52.033 --> 00:01:53.743 because it's actually a range 00:01:53.743 --> 00:01:56.307 of about 10 or 15 pounds. 00:01:56.307 --> 00:01:59.530 You can use lifestyle choices to move your weight 00:01:59.530 --> 00:02:01.598 up and down within that range, 00:02:01.598 --> 00:02:06.003 but it's much, much harder to stay outside of it. 00:02:06.003 --> 00:02:08.030 The hypothalamus, the part of the brain 00:02:08.030 --> 00:02:09.943 that regulates body weight, 00:02:09.943 --> 00:02:12.366 there are more than a dozen chemical signals 00:02:12.366 --> 00:02:14.982 in the brain that tell your body to gain weight, 00:02:14.982 --> 00:02:18.666 more than another dozen that tell your body to lose it, 00:02:18.666 --> 00:02:21.976 and the system works like a thermostat, 00:02:21.976 --> 00:02:24.323 responding to signals from the body 00:02:24.323 --> 00:02:27.931 by adjusting hunger, activity and metabolism, 00:02:27.931 --> 00:02:31.657 to keep your weight stable as conditions change. 00:02:31.657 --> 00:02:33.759 That's what a thermostat does, right? 00:02:33.759 --> 00:02:37.191 It keeps the temperature in your house the same 00:02:37.191 --> 00:02:39.951 as the weather changes outside. 00:02:39.951 --> 00:02:42.773 Now you can try to change the temperature 00:02:42.773 --> 00:02:46.269 in your house by opening a window in the winter, 00:02:46.269 --> 00:02:50.035 but that's not going to change the setting on the thermostat, 00:02:50.035 --> 00:02:52.234 which will respond by kicking on the furnace 00:02:52.234 --> 00:02:54.671 to warm the place back up. 00:02:54.671 --> 00:02:57.993 Your brain works exactly the same way, 00:02:57.993 --> 00:03:01.136 responding to weight loss by using powerful tools 00:03:01.136 --> 00:03:02.290 to push your body back 00:03:02.290 --> 00:03:06.320 to what it considers normal. 00:03:06.320 --> 00:03:08.295 If you lose a lot of weight, 00:03:08.295 --> 00:03:12.620 your brain reacts as if you were starving, 00:03:12.620 --> 00:03:15.252 and whether you started out fat or thin, 00:03:15.252 --> 00:03:18.217 your brain's response is exactly the same. 00:03:18.217 --> 00:03:20.490 We would love to think that your brain could tell 00:03:20.490 --> 00:03:21.956 whether you need to lose weight or not, 00:03:21.956 --> 00:03:24.091 but it can't. 00:03:24.091 --> 00:03:26.984 If you do lose a lot of weight, 00:03:26.984 --> 00:03:29.283 you become hungry, 00:03:29.283 --> 00:03:32.169 and your muscles burn less energy. 00:03:32.169 --> 00:03:34.818 Dr. Rudy Leibel of Columbia University 00:03:34.818 --> 00:03:36.527 has found that people who have lost 00:03:36.527 --> 00:03:38.726 10 percent of their body weight 00:03:38.726 --> 00:03:41.549 burn 250 to 400 calories less 00:03:41.549 --> 00:03:44.057 because their metabolism is suppressed. 00:03:44.057 --> 00:03:46.487 That's a lot of food. 00:03:46.487 --> 00:03:48.711 This means that a successful dieter 00:03:48.711 --> 00:03:51.879 must eat this much less forever 00:03:51.879 --> 00:03:53.171 than someone of the same weight 00:03:53.171 --> 00:03:55.474 who has always been thin. NOTE Paragraph 00:03:55.474 --> 00:03:57.264 From an evolutionary perspective, 00:03:57.264 --> 00:03:59.808 your body's resistance to weight loss makes sense. 00:03:59.808 --> 00:04:02.944 When food was scarce, our ancestors' survival 00:04:02.944 --> 00:04:05.438 depended on conserving energy, 00:04:05.438 --> 00:04:07.691 and regaining the weight when food was available 00:04:07.691 --> 00:04:10.798 would have protected them against the next shortage. 00:04:10.798 --> 00:04:13.325 Over the course of human history, 00:04:13.325 --> 00:04:16.327 starvation has been a much bigger problem 00:04:16.327 --> 00:04:18.011 than overeating. 00:04:18.011 --> 00:04:22.242 This may explain a very sad fact: 00:04:22.242 --> 00:04:25.071 Set points can go up, 00:04:25.071 --> 00:04:27.943 but they rarely go down. 00:04:27.943 --> 00:04:30.132 Now, if your mother ever mentioned 00:04:30.132 --> 00:04:32.428 that life is not fair, 00:04:32.428 --> 00:04:35.221 this is the kind of thing she was talking about. 00:04:35.221 --> 00:04:38.259 (Laughter) 00:04:38.259 --> 00:04:41.444 Successful dieting doesn't lower your set point. 00:04:41.444 --> 00:04:42.988 Even after you've kept the weight off 00:04:42.988 --> 00:04:44.817 for as long as seven years, 00:04:44.817 --> 00:04:48.790 your brain keeps trying to make you gain it back. 00:04:48.790 --> 00:04:52.080 If that weight loss had been due to a long famine, 00:04:52.080 --> 00:04:54.409 that would be a sensible response. 00:04:54.409 --> 00:04:57.090 In our modern world of drive-thru burgers, 00:04:57.090 --> 00:05:00.547 it's not working out so well for many of us. 00:05:00.547 --> 00:05:04.290 That difference between our ancestral past 00:05:04.290 --> 00:05:06.693 and our abundant present 00:05:06.693 --> 00:05:08.982 is the reason that Dr. Yoni Freedhoff 00:05:08.982 --> 00:05:11.042 of the University of Ottawa 00:05:11.042 --> 00:05:13.743 would like to take some of his patients back to a time 00:05:13.743 --> 00:05:15.842 when food was less available, 00:05:15.842 --> 00:05:17.543 and it's also the reason 00:05:17.543 --> 00:05:19.927 that changing the food environment 00:05:19.927 --> 00:05:24.043 is really going to be the most effective solution 00:05:24.043 --> 00:05:26.153 to obesity. NOTE Paragraph 00:05:26.153 --> 00:05:29.430 Sadly, a temporary weight gain 00:05:29.430 --> 00:05:31.475 can become permanent. 00:05:31.475 --> 00:05:34.109 If you stay at a high weight for too long, 00:05:34.109 --> 00:05:36.583 probably a matter of years for most of us, 00:05:36.583 --> 00:05:41.021 your brain may decide that that's the new normal. NOTE Paragraph 00:05:41.021 --> 00:05:45.081 Psychologists classify eaters into two groups, 00:05:45.081 --> 00:05:46.699 those who rely on their hunger 00:05:46.699 --> 00:05:49.268 and those who try to control their eating 00:05:49.268 --> 00:05:55.331 through willpower, like most dieters. 00:05:55.331 --> 00:06:01.842 Let's call them intuitive eaters and controlled eaters. 00:06:01.842 --> 00:06:04.025 The interesting thing is that intuitive eaters 00:06:04.025 --> 00:06:06.656 are less likely to be overweight, 00:06:06.656 --> 00:06:10.358 and they spend less time thinking about food. 00:06:10.358 --> 00:06:14.002 Controlled eaters are more vulnerable 00:06:14.002 --> 00:06:16.865 to overeating in response to advertising, 00:06:16.865 --> 00:06:20.728 super-sizing, and the all-you-can-eat buffet. 00:06:20.728 --> 00:06:22.473 And a small indulgence, 00:06:22.473 --> 00:06:25.679 like eating one scoop of ice cream, 00:06:25.679 --> 00:06:31.289 is more likely to lead to a food binge 00:06:31.289 --> 00:06:33.186 in controlled eaters. 00:06:33.186 --> 00:06:35.113 Children are especially vulnerable 00:06:35.113 --> 00:06:38.242 to this cycle of dieting and then binging. 00:06:38.242 --> 00:06:41.071 Several long-term studies have shown 00:06:41.071 --> 00:06:45.223 that girls who diet in their early teenage years 00:06:45.223 --> 00:06:48.548 are three times more likely to become overweight 00:06:48.548 --> 00:06:50.085 five years later, 00:06:50.085 --> 00:06:52.904 even if they started at a normal weight, 00:06:52.904 --> 00:06:55.553 and all of these studies found 00:06:55.553 --> 00:06:57.860 that the same factors 00:06:57.860 --> 00:07:01.254 that predicted weight gain 00:07:01.254 --> 00:07:04.254 also predicted the development of eating disorders. 00:07:04.254 --> 00:07:05.822 The other factor, by the way, 00:07:05.822 --> 00:07:07.251 those of you who are parents, 00:07:07.251 --> 00:07:10.480 was being teased by family members 00:07:10.480 --> 00:07:11.991 about their weight. 00:07:11.991 --> 00:07:13.827 So don't do that. 00:07:13.827 --> 00:07:15.565 (Laughter) NOTE Paragraph 00:07:15.565 --> 00:07:18.201 I left almost all my graphs at home, 00:07:18.201 --> 00:07:20.494 but I couldn't resist throwing in just this one, 00:07:20.494 --> 00:07:22.907 because I'm a geek, and that's how I roll. 00:07:22.907 --> 00:07:25.386 (Laughter) 00:07:25.386 --> 00:07:27.734 This is a study that looked at the risk of death 00:07:27.734 --> 00:07:29.600 over a 14-year period 00:07:29.600 --> 00:07:32.102 based on four healthy habits: 00:07:32.102 --> 00:07:34.222 eating enough fruits and vegetables, 00:07:34.222 --> 00:07:36.448 exercise three times a week, 00:07:36.448 --> 00:07:37.824 not smoking, 00:07:37.824 --> 00:07:39.794 and drinking in moderation. 00:07:39.794 --> 00:07:41.723 Let's start by looking at the normal weight 00:07:41.723 --> 00:07:43.311 people in the study. 00:07:43.311 --> 00:07:45.198 The height of the bars is the risk of death, 00:07:45.198 --> 00:07:47.579 and those zero, one, two, three, four numbers 00:07:47.579 --> 00:07:48.825 on the horizontal axis 00:07:48.825 --> 00:07:50.858 are the number of those healthy habits 00:07:50.858 --> 00:07:52.418 that a given person had. 00:07:52.418 --> 00:07:55.407 And as you'd expect, the healthier the lifestyle, 00:07:55.407 --> 00:07:58.319 the less likely people were to die during the study. 00:07:58.319 --> 00:07:59.641 Now let's look at what happens 00:07:59.641 --> 00:08:01.487 in overweight people. 00:08:01.487 --> 00:08:03.559 The ones that had no healthy habits 00:08:03.559 --> 00:08:05.330 had a higher risk of death. 00:08:05.330 --> 00:08:07.094 Adding just one healthy habit 00:08:07.094 --> 00:08:10.556 pulls overweight people back into the normal range. 00:08:10.556 --> 00:08:13.298 For obese people with no healthy habits, 00:08:13.298 --> 00:08:16.008 the risk is very high, seven times higher 00:08:16.008 --> 00:08:18.144 than the healthiest groups in the study. 00:08:18.144 --> 00:08:22.084 But a healthy lifestyle helps obese people too. 00:08:22.084 --> 00:08:24.602 In fact, if you look only at the group 00:08:24.602 --> 00:08:26.876 with all four healthy habits, 00:08:26.876 --> 00:08:29.488 you can see that weight makes very little difference. 00:08:29.488 --> 00:08:31.544 You can take control of your health 00:08:31.544 --> 00:08:33.418 by taking control of your lifestyle, 00:08:33.418 --> 00:08:34.899 even If you can't lose weight 00:08:34.899 --> 00:08:36.635 and keep it off. NOTE Paragraph 00:08:36.635 --> 00:08:40.745 Diets don't have very much reliability. 00:08:40.745 --> 00:08:42.522 Five years after a diet, 00:08:42.522 --> 00:08:45.310 most people have regained the weight. 00:08:45.310 --> 00:08:47.792 Forty percent of them have gained even more. 00:08:47.792 --> 00:08:49.217 If you think about this, 00:08:49.217 --> 00:08:51.564 the typical outcome of dieting 00:08:51.564 --> 00:08:53.452 is that you're more likely to gain weight 00:08:53.452 --> 00:08:56.221 in the long run than to lose it. NOTE Paragraph 00:08:56.221 --> 00:08:59.075 If I've convinced you that dieting 00:08:59.075 --> 00:09:01.104 might be a problem, 00:09:01.104 --> 00:09:03.742 the next question is, what do you do about it? 00:09:03.742 --> 00:09:08.198 And my answer, in a word, is mindfulness. 00:09:08.198 --> 00:09:10.733 I'm not saying you need to learn to meditate 00:09:10.733 --> 00:09:12.725 or take up yoga. 00:09:12.725 --> 00:09:15.277 I'm talking about mindful eating: 00:09:15.277 --> 00:09:18.785 learning to understand your body's signals 00:09:18.785 --> 00:09:21.174 so that you eat when you're hungry 00:09:21.174 --> 00:09:23.516 and stop when you're full, 00:09:23.516 --> 00:09:25.694 because a lot of weight gain boils down 00:09:25.694 --> 00:09:28.760 to eating when you're not hungry. 00:09:28.760 --> 00:09:30.244 How do you do it? 00:09:30.244 --> 00:09:32.078 Give yourself permission to eat 00:09:32.078 --> 00:09:34.283 as much as you want, and then work on figuring out 00:09:34.283 --> 00:09:36.035 what makes your body feel good. 00:09:36.035 --> 00:09:39.764 Sit down to regular meals without distractions. 00:09:39.764 --> 00:09:41.563 Think about how your body feels 00:09:41.563 --> 00:09:43.617 when you start to eat and when you stop, 00:09:43.617 --> 00:09:46.104 and let your hunger decide 00:09:46.104 --> 00:09:47.572 when you should be done. 00:09:47.572 --> 00:09:49.993 It took about a year for me to learn this, 00:09:49.993 --> 00:09:51.764 but it's really been worth it. 00:09:51.764 --> 00:09:54.849 I am so much more relaxed around food 00:09:54.849 --> 00:09:57.712 than I have ever been in my life. 00:09:57.712 --> 00:10:00.277 I often don't think about it. 00:10:00.277 --> 00:10:03.010 I forget we have chocolate in the house. 00:10:03.010 --> 00:10:05.954 It's like aliens have taken over my brain. 00:10:05.954 --> 00:10:08.712 It's just completely different. 00:10:08.712 --> 00:10:11.378 I should say that 00:10:11.378 --> 00:10:14.171 this approach to eating probably won't make you lose weight 00:10:14.171 --> 00:10:17.088 unless you often eat when you're not hungry, 00:10:17.088 --> 00:10:20.986 but doctors don't know of any approach 00:10:20.986 --> 00:10:25.461 that makes significant weight loss in a lot of people, 00:10:25.461 --> 00:10:28.831 and that is why a lot of people are now focusing on 00:10:28.831 --> 00:10:30.990 preventing weight gain 00:10:30.990 --> 00:10:34.213 instead of promoting weight loss. 00:10:34.213 --> 00:10:35.749 Let's face it: 00:10:35.749 --> 00:10:39.960 If diets worked, we'd all be thin already. 00:10:39.960 --> 00:10:41.860 (Laughter) 00:10:41.860 --> 00:10:43.497 Why do we keep doing the same thing 00:10:43.497 --> 00:10:46.380 and expecting different results? 00:10:46.380 --> 00:10:48.063 Diets may seem harmless, 00:10:48.063 --> 00:10:51.781 but they actually do a lot of collateral damage. 00:10:51.781 --> 00:10:54.216 At worst, they ruin lives: 00:10:54.216 --> 00:10:56.532 Weight obsession leads to eating disorders, 00:10:56.532 --> 00:10:59.475 especially in young kids. 00:10:59.475 --> 00:11:04.353 In the U.S., we have 80 percent of 10-year-old girls 00:11:04.353 --> 00:11:06.130 say they've been on a diet. 00:11:06.130 --> 00:11:08.391 Our daughters have learned to measure their worth 00:11:08.391 --> 00:11:11.494 by the wrong scale. 00:11:11.494 --> 00:11:13.519 Even at its best, 00:11:13.519 --> 00:11:16.247 dieting is a waste of time and energy. 00:11:16.247 --> 00:11:20.469 It takes willpower which you could be using 00:11:20.469 --> 00:11:23.091 to help your kids with their homework 00:11:23.091 --> 00:11:26.707 or to finish that important work project, 00:11:26.707 --> 00:11:30.194 and because willpower is limited, 00:11:30.194 --> 00:11:34.817 any strategy that relies on its consistent application 00:11:34.817 --> 00:11:37.600 is pretty much guaranteed 00:11:37.600 --> 00:11:39.693 to eventually fail you 00:11:39.693 --> 00:11:43.542 when your attention moves on to something else. NOTE Paragraph 00:11:43.542 --> 00:11:47.474 Let me leave you with one last thought. 00:11:47.474 --> 00:11:50.377 What if we told all those dieting girls 00:11:50.377 --> 00:11:53.378 that it's okay to eat when they're hungry? 00:11:53.378 --> 00:11:55.628 What if we taught them to work with their appetite 00:11:55.628 --> 00:11:57.753 instead of fearing it? 00:11:57.753 --> 00:12:01.180 I think most of them would be happier and healthier, 00:12:01.180 --> 00:12:03.195 and as adults, 00:12:03.195 --> 00:12:06.968 many of them would probably be thinner. 00:12:06.968 --> 00:12:09.081 I wish someone had told me that 00:12:09.081 --> 00:12:12.502 back when I was 13. NOTE Paragraph 00:12:12.502 --> 00:12:14.508 Thanks. NOTE Paragraph 00:12:14.508 --> 00:12:22.867 (Applause)