Exercise and weight loss: long-term follow-up

This post is by Phil Price, not Andrew.

Waaaay back in 2010, I wrote a blog entry entitled “Exercise and Weight Loss.” I had added high-intensity interval training back into my exercise regime, and had lost 12 pounds in about 12 weeks; but around the same time, some highly publicized studies were released that claimed that exercise does not lead to weight loss in overweight people. I suggested that that claim was too strong: at best they had demonstrated that moderate-intensity exercise does not lead to weight loss in most overweight people. I am completely convinced that when I am slightly overweight, I lose weight when I do occasional high-intensity workouts.

Well, I’m back with another data point. After spending a month in hell earlier this year, during which I got no exercise, I had not only failed to lose my winter weight but had added a few pounds. When I was finally able to get to my usual spring activities, which include road biking — sometimes with high-intensity intervals — I quickly lost a couple of pounds. But then I crashed, nothing serious but enough to keep me off the bike and mostly sedentary for more than a month, and I put on some more weight, topping out at about 203 or 204 pounds, the heaviest I had been since I wrote that “Exercise and weight loss” blog post back in 2010. Already this experience would seem to contradict the suggestion that exercise doesn’t control weight: if I wasn’t gaining weight due to lack of exercise, why was I gaining it?

I was able to resume exercise in early May, and in the next six weeks I lost about six pounds. In the past few weeks I’ve lost a few more. Yesterday and today, I’ve weighed in at 193 pounds, ten pounds lighter than I was two months ago. Given past experience, I expect to remain somewhere in the 192- to 195-pound range until November, when I will start edging upwards.

So I’m reiterating the point of that eight-year-old blog post I mentioned at the top: maybe moderate-intensity exercise doesn’t lead to weight loss in most overweight people, but high-intensity exercise does lead to weight loss in me when I am somewhat overweight, and as long as I regularly do some high-intensity exercise I don’t tend to gain weight.

The broader point here is that I think researchers (and journalists) tend to over-generalize. If you do a test that subjects one group of people to one set of conditions, don’t assume the results will extend to a different set of people and/or a different set of conditions, even if the people and the conditions have some similarity to those used in the experiment. The differences can matter.

Reminder: this post is by Phil, not Andrew.