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. 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.
Results and Conclusions
- Across age groups, MVPA (moderate to vigorous physical activity) was lower in the older age groups for both men and women, whereas diet quality was higher.
- Predictably, BMI and waist circumference were also higher in the older age groups.
- Within age groups, MVPA was inversely associated with BMI and waist circumference for men and women in nearly every age group. No surprise there -- the less exercise, the bigger the belly.
- Diet quality was inversely associated with the weight status variables (i.e., better diet = less weight) only in men age 30–39, 40–49 (BMI only), and 50–59, and in women age 50–59. In the other groups, higher diet quality correlated with increased weight.
The study abstract includes these conclusions;
- There are clear age-related trends for measures of weight status, physical activity, and diet quality in American men and women.
- MVPA was very consistently related to weight status in both genders. The relation between diet quality and weight status was less consistent.
- These findings provide support for public health efforts to prevent obesity by promoting increased physical activity in adult Americans.
Here's how researcher Tate summed it up:
Americans should meet the federal physical activity guideline, 150 minutes of moderate intensity physical activity per week. If most American adults met that guideline rates of overweight and obesity would be substantially lower than they are today.