Eat less and exercise more: It's not that simple

A study that was published last year in the New England Journal of Medicine* looked at what effects diet and lifestyle changes have on long-term weight gain. We know that most weight gain happens slowly over time, at the rate of roughly 1 pound a year, but it is not clear what factors can affect weight gain over the long haul in healthy individuals.

This study investigated the relationship of several diet and lifestyle changes such as beverage choices and amount of sleep in nonobese men and women living in the United States. Changes in diet and lifestyle factors were measured at four-year intervals.

The results show that small changes in individual behaviors make a big difference in long-term weight. The average difference between those with the largest amount of weight gain and those with the smallest gain was only about three servings of vegetables per day and the equivalent of walking at a brisk pace for 2½ hours each week.

While eating more or less of any one food would change the number of calories consumed, the magnitude of weight gain was associated with specific foods and beverages. The foods associated with the most weight gain were potato chips and French fries (between 2 and 3 pounds). Other weight-gaining foods included refined grains, sweets and desserts, sugar-sweetened beverages, processed meats and unprocessed red meats.

People who gained less weight tended to eat more vegetables, fruits and nuts. A surprising result was that a daily serving of yogurt was also associated with less weight gain. The authors speculated that the probiotic bacteria in yogurt may alter gut bacteria in such a way that influences weight.

Weight gain was lowest among those who slept 6 to 8 hours a night, and was higher for those sleeping less than 6 or more than 8 hours a night. More hours of television watching appears to influence weight gain, and this may due to the opportunity for increased snacking and reduced physical activity.

What does this mean for you? Anyone interested in maintaining a healthy weight as they age can benefit from the information contained in this study. Eating more nuts, fruits, vegetables and yogurt appears to reduce weight gain over time, while consuming starches such as potatoes and processed foods high in fat and sugar can increase weight gain. A habitual imbalance of 50 to 100 calories a day may be enough to result in the gradual weight gain observed in most people.


*Changes in diet and lifestyle and long-term weight gain in women and men.
Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB.
N Engl J Med. 2011 Jun 23;364(25):2392-404.