According to a series of three studies published in today’s issue of the New England Journal of Medicine, small changes like eating fewer potato chips, drinking less pop and sleeping better could help prevent long-term weight gain, the CBC reports. Potato chips were the worst offender, according to Harvard University researchers. The team looked at lifestyle factors and weight gain every four years among three separate groups of 50,422 and 47,898 women, and 22,557 men, all free of obesity or chronic disease when the study started over 12 to 20 years. Physical activity and TV-viewing influenced changes in weight, and the foods associated with the most weight gain included potato chips; other potato-based foods; sugary drinks; and unprocessed and processed meats. Meanwhile, some foods were associated with weight loss, like vegetables, whole grains, and yoghurt.