Food choices have important associations with weight gain

A new study from Harvard researchers about dietary and other lifestyle patterns associated with weight gain in middle-age adults gives us important new information about the value of making healthy food choices. Mozaffarian and colleagues combined data from three major studies that collected data every four years from more than 120,000 women and men over a period of several years (1986-2006, 1991-2003, and 1983-2006). The men and women in these studies were mostly white and relatively well educated. They gained an average of almost a pound a year during these studies.

The people in this aggregate of three large studies were found to have gained more weight as they ate more potato chips, potatoes (especially French fries), sugar-sweetened beverages, unprocessed red meats, and processed meats. Conversely, the foods associated with lower weight gains were vegetables, whole grains, nuts, and yogurt. Other than yogurt, most dairy foods were relatively neutral. Weight change tended to be greater for alcohol users, people who had previously smoked or quit smoking, people with less than 6 or more than 8 hours of sleep per day, and people who spent more time watching TV. People who were more physically active tended to gain less weight.

According to the researchers, “Higher fiber content and slower digestion of [vegetables, nuts, fruits and whole grains] would augment satiety, and their increased consumption would also displace other, more highly processed foods in the diet, providing plausible biologic mechanisms whereby persons who eat more fruits, nuts, vegetables, and whole grains would gain less weight over time” and “overall, our analysis showed divergent relationships between specific foods or beverages and long-term weight gain, suggesting that dietary quality (the types of foods and beverages consumed) influences dietary quantity (total calories).”

The findings of this study provide strong evidence that food choices, along with proper exercise and sleep, play an important role in determining how much weight adults tend to gain over time. In addition, the foods associated with less tendency to gain weight are consistent with the basic messages of the 2010 Dietary Guidelines for Americans and MyPlate, especially “make half your plate fruits and vegetables,” “make at least half your grains whole grains,” and “drink water instead of sugary drinks.”

Source: 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;364:25.