Stanford, CA — More than diet, lack of exercise is associated with rising rates of obesity in the U.S., researchers at Stanford University School of Medicine write in an article to be published in The American Journal of Medicine in August.
The observational study examined data from the National Health and Nutrition Examination Survey (NHANES) conducted between 1988 and 1994 of 17,430 participants as well as an additional 5,000 volunteers annually between 1995 and 2010. Among the information analyzed were responses to questions on the frequency, duration and intensity of exercise for the previous month.
Researchers found that between 1988 and 2010, the percentage of women who reported no physical activity rose from 19 to 52 percent and for men, the rate jumped from 11 to 43 percent. Average body mass index (BMI) increased 0.37 percent per year in both men and women, while average waist circumference grew by 0.37 percent per year in women and 0.27 percent per year in men. Younger women had the largest increases.
Further, there was a concomitant rise in the rate of obesity and abdominal obesity, from 25 to 35 percent in women and from 20 to 35 percent in men. However, daily calorie consumption varied little throughout the period, and trends in BMI and waist size were associated with physical activity, not caloric intake, the authors write.
Obesity and abdominal obesity are associated with increased risk of cardiovascular disease, various cancers, type 2 diabetes and death from these diseases.