Specific dietary and lifestyle behaviors are independently associated with long-term weight gain, according to a study published in the June 23 issue of the New England Journal of Medicine.
The conventional weight-loss strategy, “eat less and exercise more” is not an adequate plan for preventing long-term weight gain.
Harvard researchers on the study, led by Dariush Mozaffarian, M.D., Dr.P.H, indicated that the quality of the food one eats, not necessarily the quantity, is a better indicator of weight gain over time. With the recent study, “Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men,” the researchers were able to connect particular foods to weight-gain predictions.
The research included 120,877 U.S. men and women, free of chronic disease, including baseline obesity. Follow-up periods on the study included 1986-2006; 1991-2003; and 1986-2006, for three separate cohorts. Relationships between lifestyle factors and weight change were evaluated at 4-year intervals, with various adjustments made for age, baseline BMI, and lifestyle factors. Researchers found that cohort-specific results, as well as sex-specific results, were similar.
"For diet, conventional wisdom often recommends 'everything in moderation,' with a focus only on total calories consumed," said Dr. Mozaffarian, an associate professor of medicine and epidemiology at Harvard Medical School and Brigham and Women's Hospital, reported Time Healthland. "Our results demonstrate that the quality of the diet — the types of food and beverages that one consumes — is strongly linked to weight
The investigators found that the participants gained an average of 3.35 lbs in every four-year period.
Potato chips were the worst culprit, causing people to gain 1.69 pounds, followed by potatoes in general, which caused people to gain 1.28 pounds. (French fries were worse than boiled or mashed potatoes.) This, explained Dr. Mozzafarian, could be because starches and refined carbohydrates produce bursts in blood glucose and insulin, increasing hunger and thus upping the total amount of food people eat at their next meal.
Sugary beverages accounted for a one pound weight gain, while alcohol caused people to gain an average of 0.41 pounds over four years. Unprocessed meats accounted for a 0.95-pound uptick in weight, while processed meats were right behind at 0.93 pounds
Increased daily servings of vegetables, whole grains, fruits, nuts, and yogurt were significantly inversely associated with weight change.
People who added a daily serving of vegetables lost an average of 0.22 pounds over four years, the researchers found. People who added whole grains lost 0.37 pounds, and those who ate fruits shed almost half a pound. Nuts and yogurt also resulted in weight loss. Yogurt, in fact, prevented 0.82 lbs. of weight gain over time, a finding that Mozaffarian indicated was unexpected and in need of additional study.
Combined dietary changes correlated with considerable differences in weight change. Physical activity, alcohol, smoking, sleep, and television watching were independently associated with weight change.
Those who exercised more tended to gain less, while those who slept less than six hours and more than eight hours tended to gain more. Data also indicated that each additional alcoholic beverage per day added 0.41 lbs. every four years.
"Specific dietary and lifestyle factors are independently associated with long-term weight gain, with a substantial aggregate effect and implications for strategies to prevent obesity," the authors write.