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No pills, no workouts, no punishing diets. The easiest way to drop weight could simply be this: Clocking eight hours of shut-eye every night.

Just last year, Swedish researchers discovered that when well-rested, people burn 5 to 20 per cent more calories than when they were sleep-deprived.

The problem is many of us don’t spend enough time under the covers. In the whirlwind of working life, it’s sometimes a badge of honour to brag about surviving all-nighters. Disturbing as that is, we have all heard how close to a quarter of Singaporean adults feel sleep-deprived based on a Philips Index for Health and Well-being, a global health survey. Around 72 per cent of them say it’s because they sleep late (or rise early), while a worrying 43 per cent are kept up at night by stress.

The science of snooze

Could sleep tip the scales in your favour? There’s good cause to think so. Being sleep-deprived drives the hormones that regulate your appetite haywire. The key players in this equation are two chemicals: ghrelin, also called the “hunger hormone” because it stimulates appetite; and leptin, which sends signals to your brain telling it you’re full.

“When you don’t get enough sleep, your leptin levels go down, while ghrelin, up,” says neurologist Dr Lim Li Ling, president of the Singapore Sleep Society. “The combined effect of this leads to overeating, causing you to gain weight.”

Last year, the New York Obesity Research Center at St. Luke’s-Roosevelt Hospital tracked the sleeping and eating habits of 30 men and women. In one session, the participants slept nine hours a night. In another, they clocked just four hours of rest.

The results spoke volumes: When people were sleep-deprived, they snacked on an average of 2,800 calories compared to 2,500 when they were well-rested – the equivalent of scoffing down an extra croissant per day. If that doesn’t sound like a lot, don’t forget that it takes an hour of brisk walking to burn off that pastry.

The fi ndings are also linked to how people can make poorer choices when they are tired.

“When you’re tired, the first thing you think about is reaching for that bag of chips,” says Dr Kenny Pang, director of the Pacific Sleep Centre, a private clinic in Orchard Road specialising in sleep disorders. “So it’s a double whammy. Not only are your appetite hormones out of whack, you also have an instinctive impulse to snack so you’ll get the energy to stay awake.”

The New York study found that their sleep-deprived subjects acquired a taste for high-fat and -protein comfort foods that pack on the kilos. Ice cream was a hot favourite.

And then there’s sluggishness to battle. When you’re tired, you’re more likely to stay in bed than trudge to the gym. It becomes harder to sustain your workout routine.

“If you’re getting only four to five hours of sleep, then sleeping more can help you to lose weight,” Dr Lim sums up. “But if you’re already clocking seven to eight hours, it may not make much difference.”

It’s also the quality – not quantity – of sleep that matters. If you have a sleep disorder, for instance, that’s what’s messing up your rest. Get it fixed rather than just clocking in more hours.

The circle of flab

In some cases, those late nights can lead to a recurrent cycle of bad sleep and weight gain. Overweight people are more predisposed to sleep apnoea (or snoring), where you can suffer abnormal pauses in breath for up to 30 times an hour, or 200 instances in a night. The next day, you wake up feeling lethargic because your brain hasn’t been fed with enough oxygen and craves fuel to rev up your energy levels. And that’s when the snacking begins – with a vengeance.

It’s a vicious circle. The more you eat, the fatter you get, increasing your chances of sleep apnoea. And when that happens, you get even hungrier.

The cure for this disorder ranges from corrective surgery to using a special machine with a mask that pumps air through your throat. And, of course, losing weight.

While sleeping well should be part of your weight-loss programme, don’t expect to drop kilos overnight. Another caveat: Popping sleeping pills to knock you out will not do it either.

Doctors repeatedly advise that the best tactic is to combine quality rest with a healthy diet and regular exercise. Everyone’s sleep needs diff er, so use your judgement. The right amount of sleep is when you wake up refreshed and have energy to get through the day.

Your sleep-well cheat sheet

1. No phone, no television
Restrict your use of both of these items at least an hour before bedtime. Studies show that the artificial light from their screens can suppress the release of the sleep-promoting hormone melatonin.

2. No supper
The stomach acids digesting your food can flow up your gut when you’re lying flat in bed, says Dr Lim. It’s called acid reflux and it disrupts sleep. Have your last heavy meal at least four hours before bed.

3. Have a bedtime ritual
Don’t do anything stimulating before bed like playing a competitive game or having an intense discussion, says Dr Pang. Instead, try reading, listening to music or taking a warm bath – anything relaxing that’ll help you wind down.

4 Set the mood
We sleep best in a cool, dark and quiet room. Use eye shades or ear plugs, and make sure you feel cool and comfortable. Sleeping and waking up at the same times “anchor” your body clock. Try to stick to your hours, even on weekends.

This story was first published in HerWorld Fit & Fab Issue #1, 2012.

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