2023
年竟岗
生产
核算
演讲
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竟岗生产核算员演讲稿
;re thinking about what to have for dinner.
your brain also has its own sense of what you should 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 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 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 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 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 hungry, 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 less 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 protected 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 she 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 modern 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, 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 dieters. let's call them intuitive eaters and controlled eaters. the interesting thing is that intuitive eaters are less likely to be overweight, and they spend less time thinking about food. controlled eaters are more vulnerable to overeating in response to advertising, super-sizing, and the all-you-can-eat buffet. and a small indulgence, like eating one scoop of ice cream, is more likely to lead to a food binge in controlled eaters. children are especially vulnerable to this cycle of dieting and then binging.
several long-term studies have shown that girls who diet in their early teenage years are three times more likely to become overweight five years later, even if they started at a normal weight, and all of these studies found that the same factors that predicted weight gain also predicted the development of eating disorders. the other factor, by the way, those of you who are parents, was being teased by family members about their weight. so don't do that. (laughter)
i left almost all my graphs at home, but i couldn't resist throwing in just this one, because i'm a geek, and that's how i roll. (laughter) this is a study that looked at the risk of death over a 14-year period based on four healthy habits: eating enough fruits and vegetables, exercise three times a week, not smoking, and drinking in moderation. let'