It’s that nearly weightless packet of potato chips – which you flip so absent mindedly into your shopping cart year after year – that is the real culprit behind the weight gain you’ve been so nervously monitoring.
Potato chips top the list of foods associated with long-term weight gain, according to a Harvard School of Public Health study published Thursday.
The study, which explored the effects of diet and lifestyle factors on people’s tendency to gain or shed weight over a long period of time, found that potatoes, sugar-sweetened beverages, unprocessed red meats and processed meats were the most significant factors affecting weight gain among research participants.
The study was published in the New England Journal of Medicine.
Dariush Mozaffarian, associate professor of medicine and epidemiology at Harvard School of Public Health, Brigham and Women’s Hospital and Harvard Medical School, led the research, comprising three studies, that tracked over a period of 12 to 20 years the effect of diet and lifestyle on weight change in more than 120,000 people from around the U.S. After every four years, evaluations were done with regard to diet and lifestyle and weight gain.
Researchers found that research participants gained about 3.35 pounds every four years. Over a period of 20 years, in some cases, the cumulative weight gain was as much as 17 pounds.
“The message here is that the type and quality of food and beverage one eats are incredibly important,” said Mozaffarian.
But what is it about potatoes? Walter C. Willett, a co-author of the study explained in an interview with MSNBC.
“Some foods like potatoes, we eat in a cooked state and we digest those foods very quickly. They turn to blood sugar very rapidly ... and they don’t leave us satisfied for a long period of time,” which leads to excessive snacking.
The study also listed foods that actually help in weight loss. These included vegetables, whole grains, fruits, nuts, and yogurt.
The study also identified lifestyle habits that affect weight change. Physical activity, not unexpectedly, helped shedding weight, whereas sleeping more than eight or less than six hours every night led to weight gain. Alcohol use too contributed in putting on weight. As for smoking, new quitters tended to gain weight, though smokers usually lost weight. The study also pointed that watching television was also associated with weight gain.
“Most of the factors we looked at actually had been studied before. We’ve seen each of those aspects, like sugary beverages related to more weight gain, one at a time,” said Willett, the chair of Department of Nutrition at the School of Public Health. “But what we did here was put all these pieces together.”
The choice of food that one eats, however, is the key to effective weight control.
“There is no magic bullet for weight control,” said another study leader, Dr Frank Hu. “Diet and exercise are important for preventing weight gain, but diet clearly plays a bigger role.”
The study was funded by the National Institutes of Health and a foundation, while several researchers reported receiving fees from drug and nutrition companies.