1、此资料由网络收集而来，如有侵权请告知上传者立即删除。资料共分享，我们负责传递知识。TED英语演讲稿：为什么节食减肥没效果？简介：在美国，80%的女孩在她们10岁的时候便开始节食。神经学家sandra aamodt结合自己的亲身经历，讲述大脑是如何控制我们的身体的。节食减肥为何没效果来听听她的说法吧!three and a half years ago, i made one of the best decisions of my life. as my new year's resolution, i gave up dieting, stopped worrying about my
2、 weight, and learned to eat mindfully. now i eat whenever i'm hungry, and i've lost 10 pounds.this was me at age 13, when i started my first diet. i look at that picture now, and i think, you did not need a diet, you needed a fashion consult. (laughter) but i thought i needed to lose weight,
3、 and when i gained it back, of course i blamed myself. and for the next three decades, i was on and off various diets. no matter what i tried, the weight i'd lost always came back. i'm sure many of you know the feeling.as a neuroscientist, i wondered, why is this so hard obviously, how much
4、you weigh depends on how much you eat and how much energy you burn. what most people don't realize is that hunger and energy use are controlled by the brain, mostly without your awareness. your brain does a lot of its work behind the scenes, and that is a good thing, because your conscious mind
5、- how do we put this politely - it's easily distracted. it's good that you don't have to remember to breathe when you get caught up in a movie. you don't forget how to walk because you're thinking about what to have for dinner.your brain also has its own sense of what you should
6、weigh, no matter what you consciously believe. this is called your set point, but that's a misleading term, because it's actually a range of about 10 or 15 pounds. you can use lifestyle choices to move your weight up and down within that range, but it's much, much harder to stay outside
7、of it. the hypothalamus, the part of the brain that regulates body weight, there are more than a dozen chemical signals in the brain that tell your body to gain weight, more than another dozen that tell your body to lose it, and the system works like a thermostat, responding to signals from the body
8、 by adjusting hunger, activity and metabolism, to keep your weight stable as conditions change. that's what a thermostat does, right it keeps the temperature in your house the same as the weather changes outside. now you can try to change the temperature in your house by opening a window in the
9、winter, but that's not going to change the setting on the thermostat, which will respond by kicking on the furnace to warm the place back up.your brain works exactly the same way, responding to weight loss by using powerful tools to push your body back to what it considers normal. if you lose a
10、lot of weight, your brain reacts as if you were starving, and whether you started out fat or thin, your brain's response is exactly the same. we would love to think that your brain could tell whether you need to lose weight or not, but it can't. if you do lose a lot of weight, you become hun
11、gry, and your muscles burn less energy. dr. rudy leibel of columbia university has found that people who have lost 10 percent of their body weight burn 250 to 400 calories less because their metabolism is suppressed. that's a lot of food. this means that a successful dieter must eat this much le
12、ss forever than someone of the same weight who has always been thin.from an evolutionary perspective, your body's resistance to weight loss makes sense. when food was scarce, our ancestors' survival depended on conserving energy, and regaining the weight when food was available would have pr
13、otected them against the next shortage. over the course of human history, starvation has been a much bigger problem than overeating. this may explain a very sad fact: set points can go up, but they rarely go down. now, if your mother ever mentioned that life is not fair, this is the kind of thing sh
14、e was talking about. (laughter) successful dieting doesn't lower your set point. even after you've kept the weight off for as long as seven years, your brain keeps trying to make you gain it back. if that weight loss had been due to a long famine, that would be a sensible response. in our mo
15、dern world of drive-thru burgers, it's not working out so well for many of us. that difference between our ancestral past and our abundant present is the reason that dr. yoni freedhoff of the university of ottawa would like to take some of his patients back to a time when food was less available
16、, and it's also the reason that changing the food environment is really going to be the most effective solution to obesity.sadly, a temporary weight gain can become permanent. if you stay at a high weight for too long, probably a matter of years for most of us, your brain may decide that that's the new normal.psychologists classify eaters into two groups, those who rely on their hunger and those who try to control their eating through willpower, like most