Thursday, December 25, 2014

Anecdote - exercise and weight control. It takes a lot.

This is pure anecdote, but it’s not inconsistent with the past decade of research.

Once upon a time I used to advise patients to lose weight through diet and exercise. This advice was not as spectacularly bad, in retrospect, as my advice to use estrogen to prevent osteoporosis. Still, it hasn’t held up well.

We now believe (never use the word “know” when it comes to medicine) that weight loss for the overweight is approximately impossible. If weight loss were a medical procedure it would never get FDA approval. The best we can do, for most people, seems to be weight control.

And, by overweight, I mean you and I. The medical standard for ideal weight is skinny.

We need a Pill. Which is kind of hard, because we’re fighting 2.5 billion years of evolution — organisms never get enough energy. In the meantime public health interventions focus on diet changes and increased activity. The latter might help diet, especially if it involves muscle development, and we now think of exercise as spectacularly good even if it doesn’t lead to much weight loss.

Even so, there is physics. Surely if one exercises enough, and has some rough dietary discipline, it should be possible to actually lose weight. Which brings me to anecdote, because this kind of thing is hard to study for reasons that will become obvious.

Two years ago, fed up with the inevitable fattiness of my 54 yo body, and motivated by research on the relationship between exercise and cognitive function, I took advantage of income and increased my exercise level. I’d always been relatively active, but over the past two years I went to a consistent exercise level well above anything in my youth (except for bicycling from Vancouver to LA — which took me down past skinny because I didn’t have enough money to eat).

This actually worked. I can keep my BMI at the (high!) end of ideal, about 14 lbs below my baseline, while eating roughly the same diet including, on occasion, beer, pie, pizza, and pastry. Also bread.

It works — but it takes a lot of exercise. To stay at an ideal BMI on my diet I need to do something like

  • Do CrossFit 3 times a week. (I can’t seem to do more, even with scaling my old body needs time to heal.)
  • Do a two hour road bike ride at least once a week.
  • Do a 1/2 mile swim, 5 mile walk, or 10 mile inline skate once a week.
  • Do a multi-hour high intensity mountain bike outing once a week (without head injury, hopefully)

It’s a fine balance, in winter I lose the biking and gain about 4-5 lbs. (Yeah, I’m getting a fat bike next year. Global warming sucks - I miss Nordic Skiing.)

This is so much exercise no clinical trial is going to risk it on a population over 35 — we all have heart disease. I really didn’t think it was going to take this much. I do enjoy exercise, but it’s easy to see why it hasn’t worked out as a weight control tool. The exception, again, proves the rule.

Update 5/1/2023: I came across this post recently. I can now say this has been true for me for over 8 years now. My exercise distribution is different but total intensity and time is similar. It's a lot of time, I couldn't spend that much time exercising when my children were younger or if my work hours were longer.

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