Why night owls might gain more weight

Young adults who tend to stay up late and wake up later have, on average, higher body mass index, waist size, and waist-to-hip ratio than those with earlier sleep patterns, even when physical activity is accounted for. This suggests that their internal body clock may influence behaviors like eating at irregular times or eating less attentively, which could relate to higher body fat levels.

People who pay less attention to their hunger and fullness signals tend to have higher body mass index, larger waist size, and higher waist-to-hip ratios, suggesting that this lack of awareness may increase obesity risk even when diet quality is accounted for.

People who report stronger urges to eat in response to food cues, even when not hungry, tend to have higher body mass index, larger waist size, and higher waist-to-hip ratios, which are indicators of increased obesity risk, regardless of how healthy their diet is.

People who eat at significantly different times on weekdays versus weekends tend to have longer daily eating periods, greater mismatch between their social schedule and biological clock, and less sleep.

People who naturally wake up and feel most alert in the morning tend to follow the Mediterranean diet more closely and practice mindful eating more often than those with other daily rhythms.