Burning the midnight oil and weight gain

Night owls who consistently stay up late at night put themselves at higher risks for weight gain. People who burn the midnight oil typically consume more calories in the evening and eat more fast food than 'early to bed, early to rise' types.

Researchers examined 51 Americans averaging 30 years of age. Twenty-three typically went to bed by about 3:45 a.m. and woke up by 10:45 a.m. The rest, considered normal sleepers, were in bed by 12:30 a.m. and up by 8 a.m. It was found that people who stayed up late consumed an average 248 more calories daily. The diet of the night owls also included twice as much fast food, more non-diet sodas and only half as many fruits and vegetables as those with earlier sleep times. These extra calories were typically consumed at dinner and late in the evening. The study also found that those who regularly stayed up late had a higher body mass index than normal sleepers.

The extra daily calories can mean a significant amount of weight gain - one kg per month - if they are not balanced by more physical activity. The researchers suggest the reason behind the weight gain may be that healthier foods are not readily available at night, or that night owls tend to prefer foods that are higher in calories. The study concludes that eating habits are linked to sleeping patterns, and that when you eat may be just as important as what you eat.

Human bio-rhythm of sleep and metabolism are synchronised to the daily rotation of the earth, so that when the sun goes down you are supposed to be sleeping, not eating. When sleep and eating are not aligned with the body's internal clock, it can lead to changes in appetite and metabolism, which could lead to weight gain. The researchers also pointed out that people who eat unhealthy foods at the wrong time of day may increase their risk of stroke, heart disease and gastrointestinal disorders.