Putting aside a 1-ounce bag of potato chips each day in favor of yogurt can save almost a pound of weight gain every four years, according to a Harvard University analysis of the dietary habits of 120,000 Americans.
People in the U.S. add almost 1 pound a year on average, with those who consume lots of potato chips packing on the most weight and yogurt eaters cutting heft, according to the report published yesterday in the New England Journal of Medicine. A daily serving of potato chips over a 20-year period led to an extra 1.69 pounds (0.8 kilograms) every four years, while yogurt helped people lose about 0.82 pounds, the study found.
Researchers also analyzed how exercise and sleep affect weight gain. The study reinforces previous findings and may help people reassess their behavior to control their weight, said F. Xavier Pi-Sunyer, director of the New York Obesity Research Center at St. Luke’s-Roosevelt Hospital Center. About 68 percent of American adults are overweight, raising their risk of diabetes and heart disease, a 2008 U.S. survey found.
“These findings underscore the importance of making wise food choices in preventing weight gain and obesity,” said senior study author Frank Hu, a professor of nutrition and epidemiology at Harvard School of Public Health, in a statement. “The idea that there are no ‘good’ or ‘bad’ foods is a myth that needs to be debunked.”
Starches Versus Nuts
Study participants gained about 3.35 pounds during a four-year period, leading to weight gain of 16.8 pounds over 20 years. Those who ate more starches or processed foods, such as potato chips, gained about 4 pounds more every four years than those whose diets had more natural fiber, healthy fats and proteins. Eating nuts, for example, lowered weight by 0.57 pounds; mashed, boiled or fried potatoes added 1.28 pounds.
The single worst food for weight gain may be French fries, according to the study. When the researchers conducted a secondary analysis focused on potatoes, they found that French fries contributed to an extra 3.35 pounds every four years.
“Conventional wisdom often recommends ‘everything in moderation,’ with a focus only on total calories consumed, rather than the quality of what is consumed,” said study author Dariush Mozaffarian, an associate professor of medicine and epidemiology at Harvard School of Public Health in Boston, in a June 21 e-mail. “Our results demonstrate that the quality of the diet, the types of foods and beverages that one consumed, is strongly linked to weight gain.”
The researchers analyzed three studies -- the Nurses’ Health Study, the Nurses’ Health Study II and the Health Professionals Follow-up Study. The report examined lifestyle factors and weight gain every four years over 12 to 20 years. The review included 120,877 U.S. women and men who at the start of the studies weren’t obese and were free of chronic diseases.
The researchers also found that those who had the greatest increase in physical activity gained 1.76 fewer pounds every four years than those who had the greatest decrease in activity.
Adding an alcoholic drink a day increased weight as did sleeping less than six hours or more than eight hours a night, the study showed. Also, watching an additional hour of television a day added 0.31 pounds.
People who quit smoking within the previous four years gained 5.17 pounds versus those who had never smoked, the researchers found.
The three studies included people who were educated and mostly white. Pi-Sunyer said more research is needed to see if the results are true in other populations.
“It’s another way to support a healthy lifestyle and that also includes more physical activity, being less sedentary, less beverages, whether it’s sweetened or alcohol, things that we’ve know before,” Pi-Sunyer, who wasn’t an author of yesterday’s study, said in a June 21 telephone interview. “It’s nice to have such a long study confirming all this.”