How Much Exercise to Sustain Weight Loss?

How Much Exercise to Sustain Weight Loss?
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What role has inactivity played in the obesity epidemic and how much should we be exercising?

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Right now, “[a]lmost two thirds of Americans are overweight.” And by 2030, more than half our population may be clinically obese. “[C]hildhood obesity has tripled,” and most of them will grow up to be overweight as well. “The United States may be in the midst of raising the first generation since [our] nation’s founding that will have a shorter predicted life span than that of the previous generation.”

The food industry blames inactivity; we just need to move more. But, what is “the role of exercise in the treatment of obesity”?

“There is considerable debate in the medical literature today about whether physical activity has any role whatsoever in the epidemic of obesity that has swept the globe since the [19]80s.” The increase in calories per person is “more than sufficient to explain the US epidemic of obesity.” In fact, if anything, the level of physical activity over the last few decades has actually gone up in both Europe and North America.

“This…has important policy implications.” Yes, we still need to exercise more, but “the priorities for reversing the obesity epidemic should focus on…the…overconsumption” of calories. To work off the increased calorie intake—which, for kids, is like an extra can of soda and small fries, compared to what they were eating back in the 70s, and, for adults, about an extra Big Mac. To work that off, we’d have to walk, like, two hours a day, seven days a week. So, exercise can prevent weight gain, but “the amount required to prevent weight gain may be closer to twice” the current recommendations.

Public health advocates have been experimenting with including this kind of information. The fast food menu labeled with calories, and the number of miles to walk to burn those calories, appeared to be “most effective in influencing the selection of lower-calorie meals.”

Now, exercise alone may have a small effect, and that small effect can make a big difference on a population scale. A one percent decrease in BMI nationwide might prevent millions of cases of diabetes and heart disease, thousands of cases of cancer.

But, why don’t we lose more weight from exercise? It may be because we’re just not doing it enough. “[T]he small magnitude of weight loss observed from the majority of…exercise interventions” (you know, where they make people exercise) “may be primarily due to [how] low [the] doses [are] of prescribed exercise…”

People tend to overestimate how many calories are burned by physical activity. For example, there’s this myth that “[a] bout of sexual activity burns a few hundred calories.” So, hey, you could get a side of fries with that. But, if you actually hook people up, and measure energy expenditure during the act (and your study subjects don’t get too tangled up with all the wires and hoses), though it may be nearly the metabolic equivalent of calisthenics, “[g]iven that the average bout of sexual activity only lasts about six minutes, a [young] man…might expend approximately 21 [calories] during sexual intercourse.” Of course, he would have spent roughly one-third of that just lying around watching TV, just basal metabolism. So, “the incremental benefit is plausibly on the order of 14 [calories].” So, maybe we could have, like, one fry with that.

Please consider volunteering to help out on the site.

Images thanks to Will_Arthur via flickr

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Right now, “[a]lmost two thirds of Americans are overweight.” And by 2030, more than half our population may be clinically obese. “[C]hildhood obesity has tripled,” and most of them will grow up to be overweight as well. “The United States may be in the midst of raising the first generation since [our] nation’s founding that will have a shorter predicted life span than that of the previous generation.”

The food industry blames inactivity; we just need to move more. But, what is “the role of exercise in the treatment of obesity”?

“There is considerable debate in the medical literature today about whether physical activity has any role whatsoever in the epidemic of obesity that has swept the globe since the [19]80s.” The increase in calories per person is “more than sufficient to explain the US epidemic of obesity.” In fact, if anything, the level of physical activity over the last few decades has actually gone up in both Europe and North America.

“This…has important policy implications.” Yes, we still need to exercise more, but “the priorities for reversing the obesity epidemic should focus on…the…overconsumption” of calories. To work off the increased calorie intake—which, for kids, is like an extra can of soda and small fries, compared to what they were eating back in the 70s, and, for adults, about an extra Big Mac. To work that off, we’d have to walk, like, two hours a day, seven days a week. So, exercise can prevent weight gain, but “the amount required to prevent weight gain may be closer to twice” the current recommendations.

Public health advocates have been experimenting with including this kind of information. The fast food menu labeled with calories, and the number of miles to walk to burn those calories, appeared to be “most effective in influencing the selection of lower-calorie meals.”

Now, exercise alone may have a small effect, and that small effect can make a big difference on a population scale. A one percent decrease in BMI nationwide might prevent millions of cases of diabetes and heart disease, thousands of cases of cancer.

But, why don’t we lose more weight from exercise? It may be because we’re just not doing it enough. “[T]he small magnitude of weight loss observed from the majority of…exercise interventions” (you know, where they make people exercise) “may be primarily due to [how] low [the] doses [are] of prescribed exercise…”

People tend to overestimate how many calories are burned by physical activity. For example, there’s this myth that “[a] bout of sexual activity burns a few hundred calories.” So, hey, you could get a side of fries with that. But, if you actually hook people up, and measure energy expenditure during the act (and your study subjects don’t get too tangled up with all the wires and hoses), though it may be nearly the metabolic equivalent of calisthenics, “[g]iven that the average bout of sexual activity only lasts about six minutes, a [young] man…might expend approximately 21 [calories] during sexual intercourse.” Of course, he would have spent roughly one-third of that just lying around watching TV, just basal metabolism. So, “the incremental benefit is plausibly on the order of 14 [calories].” So, maybe we could have, like, one fry with that.

Please consider volunteering to help out on the site.

Images thanks to Will_Arthur via flickr

Doctor's Note

I previously touched on this in my video Diet vs. Exercise for Weight Loss?

Don’t get me wrong–exercise is wonderful! Check out, for example:

Best to stick to foods rich in nutrients but poor in calories: Calculate Your Healthy Eating Score. It’s cheaper too. See Best Nutrition Bang for Your Buck.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

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