The myth that late-night eating causes weight gain might have originated from a decade-old study that found that “diet-induced thermogenesis” or DIT (the extra calories it takes to digest and assimilate foods) was higher after breakfast than after lunch, and higher after lunch than after dinner (at least in men). These results suggested that more calories are used up and so are not stored as fat when consumed earlier in the day. No research since has added credence to the theory. Granted, there probably is a slight fat-storing effect when a person eats a large dinner or evening snack and then sits around all night compared to eating a large breakfast followed by an active day, but the effect is too small to make any difference in a person’s weight. However, people tend to eat junk at night, such as ice cream, chips, and buttered popcorn, and too many calories any time of the day will lead to weight gain.