By David Heber, M.D., Ph.D.
Specific foods and lifestyle behaviors are associated with differing rates of weight gain in the U.S. population over time. Even people who are not obese often see that they seem to gain weight as they age. This landmark study published in the New England Journal of Medicine from the Harvard School of Public Heath by Dr. Frank Hu and colleagues (1) for the first time examines which specific dietary patterns and lifestyle behaviors were more or less associated with observed weight gain. The study analyzed data from three very large groups of subjects who completed questionnaires on their dietary habits and lifestyle behaviors, and included 120,877 healthy non-obese U.S. women and men. The periods of time examined were from 1986 to 2006, 1991 to 2003, and 1986 to 2006.
The relationships between changes in lifestyle factors and weight change were evaluated at 4-year intervals. Within each 4-year period, subjects gained an average of 3.35 lb. The 4-year weight change was most strongly associated with the intake of potato chips (1.69 lb), potatoes (1.28 lb), sugar-sweetened beverages (1.00 lb), unprocessed red meats (0.95 lb) and processed meats (0.93 lb), and was inversely associated with the intake of vegetables (−0.22 lb), whole grains (−0.37 lb), fruits (−0.49 lb), nuts (−0.57 lb), and yogurts (−0.82 lb) (P≤0.005 for each comparison).
Other lifestyle factors were also independently associated with weight change (P<0.001), including physical activity (−1.76 lb across quintiles), alcohol use (0.41 lb per drink per day), smoking (new quitters, 5.17 lb; former smokers, 0.14 lb), sleep (more weight gain with <6 or >8 hours of sleep), and television watching (0.31 lb per hour per day).
The study was further validated by the fact that eating less of the foods associated with weight gain was related to less weight gain while eating less of the foods associated with weight loss was associated with weight gain. For the first time, this study has provided hard evidence for the effects of potato chips, potatoes, sugar-sweetened beverages, and red meats on weight gain which were common knowledge among dieters and doctors, but were never confirmed in research studies. These findings should lead to more targeted approaches to dietary advice for preventing weight gain or even for incorporation into dietary programs to promote weight loss. A daily excess calorie balance of about 50 to 100 calories may be sufficient to cause the gradual weight gain seen in most persons. This means that unintended weight gain occurs easily, but also that modest, sustained changes in lifestyle could mitigate or reverse such an energy imbalance.
The results of this study suggest that both individual and population-based strategies to help people consume fewer calories may be most effective when particular foods and beverages are targeted for decreased (or increased) consumption. The observed dietary changes accounted for substantial differences in weight gain, with additional contributions from changes in physical activity and television watching, thus highlighting specific lifestyle changes that might be prioritized in obesity prevention strategies. These results fit well with other research showing that certain foods lead to overuse. The old advertisement “You can’t eat just one!” applied to potato chips may translate into more weight gain over time.
(1). Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and
lifestyle and long-term weight gain in women and men. N Engl J Med. 2011 Jun