Long-term weight gain impacted by specific dietary factors

Mozaffarian D. N Engl J Med. 2011;364:2392-2404.

An analysis of three separate studies that examined the correlation between diet and weight gain revealed specific diet and lifestyle factors are independently associated with long-term weight gain.

According to the results, modest changes in specific foods and beverages, physical activity, TV watching and sleep duration were strongly linked with long-term weight gain. Changes in diet, in particular, had the strongest associations with differences in weight gain.

Published in the June issue of The New England Journal of Medicine, the study analyzed data from the Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study. The three studies were conducted during a 20-year period and all came to very similar conclusions. The analysis included 50,422 women who participated in the Nurses’ Health Study, 47,898 in the Nurses’ Health Study II and 22,557 men in the Harvard School of Public Health study. None of the participants had obesity or chronic diseases at baseline; at the end of the 20-year study period, participants gained an average of 16.8 lb, or 3.35 lb every 4-year period.

Potato chips were associated with the greatest weight gain during the study period. Each one increased daily serving was associated with a 1.69-lb weight gain every 4 years. Other potatoes, sugar-sweetened beverages, unprocessed meats and processed meats were also associated with weight gains of about 1 lb. On the other hand, increased consumption of vegetables, whole grains, fruits, nuts and yogurt were associated with less weight gain.

According to the researchers, participants who were in the lower 20% of dietary changes gained about 4 lb more every 4 years compared with participants in the top 20%.

The researchers also examined sleep habits. Results indicated that participants who got a full 6 to 8 hours of sleep each night gained less weight than those who slept less than 6 or more than 8 hours. Also, participants who were more physically active were prone to gain less weight than those who spent more time watching TV.

“Small dietary and other lifestyles changes can together make a big difference — for bad or good,” Dariush Mozaffarian, MD, associate professor in the department of epidemiology at Harvard School of Public Health, said in a press release. “This makes it easy to gain weight unintentionally, but also demonstrates the tremendous opportunity for prevention. A handful of the right lifestyles changes will go a long way.”

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