Q: I have to stay up late studying. Do my late-night snacks have a disproportionate effect on my weight compared to eating during the day?
A: The short answer to the question is, it depends.
One's basal metabolic rate, or BMR, stays relatively constant. Rather than time of day, caloric intake or physical activity, BMR is a function of body size and composition. It represents the amount of energy your body needs to maintain basic body functions not including physical activity or food digestion. It is a common misconception that metabolism slows down at night.
However, bad food choices and lack of energy expenditure can explain the positive correlation of snacking at night and weight gain. People are much more active during the day and continuously burn off calories, whereas at night, they are more sedentary. In addition, many tend to make poor food choices late at night because they are eating to stay awake, not because they are hungry. In the end, late-night snacking can contribute far more calories to one's daily intake than what is needed. Those extra calories, in turn, are stored as fat.
Still, snacking at night is acceptable as long as most of one's daily calories are consumed during a time when most people are still physically active.
