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Tuesday, April 27, 2010

Diet and exercise don't work?

In the Atlantic, Marc Ambinder wrote:Stigma might be more bearable—an unpleasant way station on the path to a thinner, healthier life—if diet and exercise, the most prescribed solutions to obesity, worked. But they don’t. Qualification: if you eat less and exercise more, you’ll lose weight. But the chances that you’ll stick with that regimen are slim, and the chances that you’ll regain the weight, and then some, are quite high. A systematic review of weight-loss programs, by Thomas A. Wadden and Adam Gilden Tsai of the University of Pennsylvania, found that the evidence that commercial and self-help weight-loss programs work is “suboptimal.” People who diet often regain more weight than they lose.

I can think of two counter examples. A friend of mine at work was diagnosed with a heart problem. It was exacerbated by a sedentary lifestyle, and his doctor wanted to immediately put him on drugs. He said, "Wait, wait. Can I solve this with a lifestyle change? Change my diet and exercise?" His doctor replied, "That doesn't work. Statistically, nobody sticks with such regiments." My friend wasn't willing to give up, however, and told the doctor, "Let me try it for a month. If that doesn't work you can put me on drugs." This guy went from zero exercise to biking to work 4-5 days a week, hiking and running with his kids on weekends, and started cutting his portion sizes and eating more greens. A month later, his doctor pronounced him completely fit, and at little risk from his cardiovascular disease. Six months later, he was still going strong, and still biking to work nearly every day. Note that if this same man had lived outside California, he probably wouldn't be able to bike through the entire winter. If he had even lived in San Francisco, his bike probably would have gotten stolen within that time period.

Example two: In 2005, I was diagnosed with osteopenia. My doctor immediately put me on a regiment of calcium and vitamin D supplements, and I embarked on a program of hiking and weight lifting, that I continue to this day (it's been 5 years). My bones are back to normal, even though doctors and others were incredulous at the improvement.

The lesson, perhaps, is that if you're a Google engineer, all these rules of thumb about lifestyle changes not working? They're probably inapplicable to you. The question in my mind is: Is there an easy way to predict what kind of persons do well with this kind of diet/exercise regime, and what kinds of persons don't?

10 comments:

Jim said...

I added one more day of biking to work and climbing to lose my extra weight. Admittedly, I've only kept the weight off for a year.

That was a cheap comment about SF.

Piaw Na said...

:-)

Keeping it off for a year is pretty good. I assume you forgot to add "so far."

Jill said...

I biked to work at Google and all my other workplaces, and in fact have seldom owned a car. My body has cheerfully and happily stayed fat, with the same proportions as those of my aunt and my grandmother, who don't exercise. Cycling makes me feel great and likely improves my health, and I don't lose weight doing it.

This fits with the results of the adoption studies done in Denmark (where good enough adoption records were kept to allow it to happen). The researchers found that adoptive children had BMIs that correlated strongly with their birth parents and didn't correlate with those of their adopted parents.

Cycling is also a great form of exercise and transport for (some of) those of us with a history of (some) joint problems. When I was at the worst of my knee pain and couldn't walk well except on flat surfaces, I could still ride my bike.

Piaw Na said...

It's definitely possible to be fat and healthy. It's also possible to be thin and unhealthy. But I don't think it's possible to be obese the way he discusses in the article and be healthy. I fully expect that your exercise habit would keep you from being obese the way some people are.

Studies also show that if you actually want to effect a change in your body shape, you have to exercise more than an hour a day. Most people simply don't put in enough time (or exercise hard enough) to affect their body shapes.

Jill said...

If you don't think I'm really fat, perhaps you don't remember me? In BMI percentile I'm well into the 90s. Yes, there are people in the world fatter than I am, but my fatness is obvious to the eye!

Your other comments are nonspecific enough that I don't know whether I was a counterexample when I was doing triathlons and the like or not. I do agree that when people get fat enough that it's extremely difficult to move, their health suffers.

Similarly, I didn't see much in the article about kinds of obesity, so I'm not sure what you mean about being obese the way he discusses in the article. It sounded to me like he was talking about possible reasons some people are fat, discussing the usual policies that are often proposed to make people get less fat, and recommending bariatric surgery.

I was fat when I was exercising more than an hour a day; I remember a swim coach telling me (though I don't know if he was right) that my body shape was why my times were commensurate with the beginning triathletes even after years of regular coached workouts, swim lessons, very good technique, and significant improvement. There are also fat Olympic athletes in the sports for which that's not a disadvantage. It's an usual body type, the fit and very fat. (I'm not currently very fit, just moderately fit)

When I worked at Google my exercise was a bicycle commute of 45 minutes round trip four or five times a week plus a variable amount of time spent playing DDR, so far more than most people in the developed world but less than the hour a day threshold.

In your original post, how are you relating what you quoted to the counterexamples you give? The quote said that losing weight by diet and exercise very seldom works in the long run, and your counterexamples are of people successfully using exercise programs to slow down or counteract medical conditions, with no mention of losing weight. Did they lose weight, or are you making a different point?

Piaw Na said...

Hm... His health became such a problem that he went for surgery to fix it. I don't think you're contemplating anything that drastic. If you can still ride a bike, you're not in trouble the way he was, pre-surgery.

Yes, body shape is pretty much genetically determined. And some people don't respond to exercise at all (apparently some 10% of people never respond to exercise no matter what they do). Google is also not a very good environment for losing weight. :-)

The first person lost weight. And I gained weight from increasing bone density.

md said...

His doctor replied, "That doesn't work. Statistically, nobody sticks with such regimens

He sounds like a pretty bad doctor if he's treating every patient as the average patient. I can imagine him telling a cancer patient "statistically, 75% of patients with your cancer die, so we just won't bother treating you because you're probably going to die anyway."

Comment for Jill: I'd say you're doing fine if you're happy with the way you look; it's only a problem if you're not. You've mentioned doing a lot of exercise; have you ever altered your diet and lost weight?

I'm a slim person and always have been, so my personal experience can be taken with a grain of salt. I tend to gain a few pounds when I eat out more. For example, if I go on vacation for a week, I gain a pound or two. I find that I have to work to lose it, but once it's gone, I maintain my weight on my normal diet. However, because I have a small appetite, I do not eat a lot of food, and I normally eat much smaller servings than are served in restaurants or as takeout. I probably get about 1500 calories a day on average.

Piaw Na said...

I disagree that he's treating every patient as the average patient. If 99% of folks don't follow diet and exercise, then he's correct about his drug prescription 99% of the time. He couldn't possibly know that this one guy he's seeing is the 1% exception.

I do the same thing with financial advice when people I don't know well ask about it. Since they don't know me well, they usually ignore me and do the opposite of what I tell them to. A year passes and they come back and tell me they should have done what I told them to do.

md said...

If 99% of folks don't follow diet and exercise, then he's correct about his drug prescription 99% of the time

That's true, but who says 99% of people won't follow diet and exercise? He would still be a poor doctor if he did not inform his patient about diet and exercise, and from your post it sounds like he did not.

If you went to a doctor with headaches, and he immediately gave you a prescription drug without asking you if you'd tried ibuprofen or aspirin, I'd consider that bad doctoring.

Finally, I don't know where you get the 99% statistic from. You can find numerous studies with conflicting results about what percent of people keep weight off with diet and exercise. Mayo clinic has a study of people who kept weight off for 2 years, and how they did it; so it's clearly possible for some people to do it. How about handing out this information, in addition to handing over a prescription?

Abhay Vardhan said...

I too had a similar experience. My cholesterol levels were very high and the doctors wanted me to take drugs. I opted for a life style change and have been regularly exercising for 8 years. Admittedly, I have regained some of the weight that I lost but I am happy to say that I have been able to sustain a lifestyle change.