A False Choice Between Exercise and Diet

“To keep obesity at bay, exercise may trump diet.” This headline from the New York Times follows a longstanding theme: a false choice between exercise and diet. Simply framing the question this way offers up bad choices.

The reason for the headline was a rat study. It showed health benefits for exercise in rats that were predisposed to obesity. The benefits were independent the diets fed to the rats. It was a small, randomized, controlled study with three groups: an exercise group, a calorie-restricted group, and a control group. Rats in the calorie-restricted group were kept sedentary and fed so that they weighed the same as the exercise group. Both of those groups stayed slimmer than rats the control group, which stayed sedentary and ate as much as they wanted.

Unsurprisingly, the active rats were healthier at the end of the experiment than the sedentary rats.

At the end of the day, though, the false choice is still false. These 30 rats don’t preempt what’s known about diet and exercise in humans. What you eat still matters for your health and staying active improves your health at any weight. The old saw – you can’t outrun a bad diet – remains true.

The real problem here comes from setting up healthy eating and staying active like some sort of bad medicine. Framed as two options that nobody really wants, we have a losing proposition. We need both good food and active lives for good health. Setting them up as pleasures to seek is the best way to succeed.

Click here for the story in the New York Times and here for the study.

Riding the Day, photograph © Keoni Cabral / flickr

Subscribe by email to follow the accumulating evidence and observations that shape our view of health, obesity, and policy.

May 5, 2016