Thursday, March 25, 2010

Exercise For An Hour A Day, Seven Days A Week

Excerpt from The Journal of the American Medical Association, March 24/31. 2010:

Objective: To examine the association of different amounts of physical activity with long-term weight changes among women consuming a usual diet.

Participants: A prospective cohort study involving 34 079 healthy US women (mean age, 54.2 years) from 1992-2007…

Conclusions: Among women consuming a usual diet, physical activity was associated with less weight gain only among women whose BMI was lower than 25. Women successful in maintaining normal weight and gaining fewer than 2.3 kg over 13 years averaged approximately 60 minutes a day of moderate-intensity activity throughout the study. “

I read this report with mixed feelings.

On the one hand, my heart sinks. I am a healthy 50 + woman with a BMI lower than 25 (last time I checked). So this study seems to be about me, and it seems to suggest that I should be exercising 60 minutes a day to avoid weight gain. And the exercise in question probably does not include strolling around the house, powering up my computer, or even dashing to my car.

If I were to ramp up my “activity”, I’d have to wear the right clothing, and I would have to sweat. And sweating by virtue of living in Florida wouldn’t count. Now, if I take into account the time it takes me to get ready to exercise, and the time it takes to revert back to a presentable state afterwards, I could be devoting up to two hours every day to exercise. Where would I find the time for that? And, more importantly, how could I muster the enthusiasm to do it?

On the other hand, if I actually did this – and why not, many people do – then I could continue merrily along for the other 22 hours a day, with not a thought about diet.

But here’s the flaw in the study, from my perspective:

“Among women consuming a usual diet…”

What “usual diet”? Is there such a thing? And whose diet is that consistent, year in and year out?

My usual diet, these days, is a tad heavy on the calories, I think. So am I to understand that if I continue to eat this way, provided that I exercise with moderate intensity 60 minutes a day, every day, I will NOT gain too much weight? Lovely!

Only I don’t think that would work for me. I don’t know about you, but I’ve always found that diet alone - without any formal exercise whatsoever - results in weight loss every time. Whereas exercise - with absolutely no adjustment to diet - just does not move that dial for me. And I’m not always a layabout on the exercise front. I do have spurts of energy, and I have been known to exercise regularly. In fact, I believe that exercise is good for my general health. But as far as weight loss goes, it’s food that does it every time.

The less I eat, the less I weigh. The more I eat, the more I weigh.

Once again, despite the glimmer of hope that this article actually inspired in me, I must acknowledge that there is just no getting around it: I will have to watch what I eat – forever! Maybe it’s just me, but the battle does seem to get harder as I get older.

Oh well, perhaps I’ll dig up my old sneakers and head out again, tomorrow. But now I need some comfort. Food, that is.

As Christiaan Barnard, South African heart transplant pioneer, said (and he would have known):

“If the poor overweight jogger only knew how far he had to run to work off the calories in a crust of bread he might find it better in terms of pound per mile to go to a massage parlor.”


  1. The 60-minutes/day, 7/days/per week protocol reminds me of the folks who take Pollan's advice to extremes (see for a great example of that). The Barnard quote is priceless, and a perfect ending to the post. Thanks for this intelligent and well-stated contribution to the annals of frustration with study results that leave us ordinary mortals in a total quandary regarding sensible, achievable approaches to good health.

  2. Recently I cancelled my membership in Weight Watchers On Line program. The plan was so inflexible and so full of gimmicks that to follow it thoroughly would leave no time for exercise.

    Worse than that, it took valuable time away from reading the excellent posts on the Raining Acorns blog. Conclusion: I'd rather be happy than thin!

  3. You hit the nail on the head when you point out the flaw of "women consuming a usual diet." That is a huge variable, to me. Also not addressed is a factor that I think influences weight more than conventionally mentioned - genetics. I think there are certain body types that are programmed to stay thinner later in life than others.

    This study may have the same effect that some of the more stringent diet advice has, as Raining Acorns points out. People may throw up their hands because they can't possibly eat the recommended amount of vegetables, or exercise for an hour a day, and then decide it is not worth exercising for even 15 minutes.

    I like cybersr's comment too!


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