Exercise, Not Diet, Has Most Impact On Weight As We Age

13 Apr

5 overweight senior men in an aquafit lesson using dumbbells | Zena Holloway via Getty Images

It won’t shock anyone to know that Americans tend to gain weight as they get older. But it is a little surprising that as Americans age and put on more body fat, the quality of their diets generally improves.

In other words, Americans do try to correct their softening midsections with things like salads and lean proteins. And, unfortunately, that doesn’t quite work, according to a recent analysis of physical activity, diet and weight among U.S. adults. Instead, whether or not a person engaged in moderate to vigorous physical activity was more likely to predict their ability to stave off age-associated weight gain.

The study, which breaks down data points from 4,999 American adults ages 20 to over 70 years old, is large enough in sample size to depict an accurate snapshot of how Americans are aging — and how their diet and exercise levels change over the years.

“Our study points to the very important impact of physical activity on weight status in U.S. adults, and in particular it points to the critical role of the age-related decline in physical activity on the increasing rates of overweight and obesity that we see with aging,” said lead researcher Russell Pate, Ph.D., of the University of South Carolina. “Our findings indicate that increasing fatness with age in U.S. adults cannot be explained by changes in the quality of the diet they consume.”

Pate took information from the National Health and Nutrition Examination Survey, which measured activity via accelerometer (a plus because it’s much more accurate than self-reported information) and recorded information on weight, body mass index, waist circumference and quality of diet. He then controlled for factors like race, ethnicity, socioeconomic status and whether or not a person smoked.

The takeaway? “Americans should meet the federal physical activity guideline, 150 minutes of moderate intensity physical activity per week,” wrote Tate. “If most American adults met that guideline rates of overweight and obesity would be substantially lower than they are today.”

Overall, Americans’ activity levels are lower thanks to sedentary jobs, technology and better mass transportation options, according to the American Heart Association. We’re paying for those conveniences with our health; about 69 percent of adults are either overweight or obese, which increases risk for diseases like diabetes, cardiovascular disease, some cancers and reproductive problems.

Pate’s research was published in the latest edition of the Medicine & Science In Sports & Exercise journal.