Are you a night owl or an early riser? If you have to haul to yourself from bed each morning after burning the midnight oil, you’re probably already a tiny bit jealous of those bright-eyed dawn worshippers – and now research suggests they could be onto something.
Staying up late and sleeping in regularly is a habit that could put you at risk of weight gain. People who go to bed late and sleep late eat more calories in the evening, more fast food, fewer fruits and vegetables, and weigh more than people who go to sleep earlier and wake up earlier, according to a new Northwestern Medicine study published in the journal Obesity.
Late sleepers consume more
The study is one of the first to explore the relationship between circadian rhythms of sleep, dietary habits and body mass index. It studied 23 ‘late’ sleepers and 28 ‘normal’ sleepers. The late sleepers nodded off at an average time of 3:34am, awoke by 10:45am, ate breakfast at noon, lunch at 2:30pm, dinner at 8:15pm and a final meal at 10pm. The normal sleepers were, on average, up by 8am, ate breakfast by 9am, lunch at 1pm, dinner at 7pm and a last snack at 8:30pm. They went to bed before 12:30am.
The late sleepers consumed 248 more calories a day, twice as much fast food and half as many fruits and vegetables as those with earlier sleep times, according to the study. They also drank more full-calorie soft drinks. The late sleepers consumed the extra calories during dinner and later in the evening when everyone else was asleep. They also had a higher body mass index, a measure of body weight, than normal sleepers.
And those calories add up to big numbers on the scales – an extra 248 calories a day equates to nearly 1kg (900g) of weight gain a month if they are not burned off with exercise.
“We don’t know if late sleepers consume the extra calories because they prefer more high-calorie foods or because there are less healthful options at night,” says co-lead author Kathryn Reid, research assistant professor in neurology at the Feinberg School of Medicine.
Genes respond to night and day
Circadian rhythms are physical, mental and behavioural changes that roughly follow a 24-hour cycle and respond primarily to light and dark.
Ten per cent of the genes in our bodies operate on a 24-hour rhythm. When a person’s body clock is thrown off, it can affect the efficiency of bodily processes such as digestion.
“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,” says senior author Phyllis Zee.
The research findings could be relevant to people who are not very successful in losing weight, Zee said. “The study suggests regulating the timing of eating and sleep could improve the effectiveness of weight management programs."
Reset your body clock
Can a night owl become a morning lark? How easy you find it to bounce out of bed in the morning could be down to your genes. A team from the University of Surrey in the UK says the ‘clock gene’ called Period 3 is responsible for a person’s preference for mornings or evenings. The gene is one of those involved in regulating the body’s internal clock.
However, it is possible to shift your body clock so that you’re more of a morning person. The Biggest Loser Club has 7 ways to make getting up easier and better manage your weight ...
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Get a routine
Try getting up at the same time each day, even on weekends and days off. Going to bed at random times wreaks havoc on your circadian rhythms.
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Exercise first thing
It doesn’t have to be a 5am thrashing with a personal trainer, just walking your dog for 20 minutes will help boost your energy levels.
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Let in the sun
Get your circadian rhythms back on track by bathing in natural light as soon as you wake up. It can also help to avoid bright lighting, such as shopping centres, in the evening.
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Cut down caffeine
One morning coffee won’t do much harm but night owls should steer clear of caffeine in the afternoon.
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Keep it quiet
Turn off the TV and laptop – bed is for sleeping!
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Wind down
Avoid late evening exercise because it can increase your temperature and disrupt your sleep pattern.
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Stick to snacks before bed
Avoid large meals before you hit the hay. Instead snack on foods containing amino acid tryptophan, such as turkey, dried dates, milk and yoghurt.