We all know that a healthy diet and regular exercise is the key to losing weight, but there’s another way to fight the flab: getting enough rest!
"Sleep deprivation means your body gets low on energy and needs to find another source of fuel to keep you awake and food is its first point of call," says fitness and nutrition expert Libby Babet (bottomsupfitness.com.au). "Levels of the hormone ghrelin are increased, which spikes your appetite, particularly for high-fat, high-kilojoule foods."
Leptin, the hormone that tells you when you're full also decreases if you are not getting enough sleep. Ouch, now you're not only eating bad foods, you're eating a lot of them. According to Libby, this ghrelin/leptin imbalance actually means you burn kilojoules at a slower rate as well.
WHAT THE SCIENTISTS SAY
Scientists at Columbia University in the US used brain scans in average-weight people to measure responses to unhealthy foods (such as pepperoni pizza and lollies) as well as healthy options (including porridge and fruit). They found that the brain's reward centre lit up more at the sight of junk food if subjects were tired.
In other US studies, activity in the front part of the brain has been found to be significantly impaired when people are sleep deprived. This is the region of the brain involved in the complex processing that encourages you to make wise choices about what you should eat. So basically when you're tired, you're more likely to reach for that Milky Way or order a takeaway pizza.
BLAST BELLY FAT
"Lack of sleep can also affect your cortisol (stress hormone) levels," says Libby. "When you're tired, cortisol sky rockets. This can lead to weight gain on your stomach because your body thinks, 'I'm stressed! Famine must be coming! I'd better store some calories in case I need 'em later!'." This doesn't mean you have to commit to 10 hours sleep every night. As adults we really only need somewhere between 6-8 hours, with 7 being the magic number.
Researchers at the University of California, San Francisco found
that reducing stress effectively prevents weight gain, even without
dieting, and participants who experienced the greatest reduction in
stress lost the most belly fat.
AVOID THE FAT GENE
A study by the University of Washington monitored 1,000 sets of twins and found that those who slept fewer than seven hours per night were likely to weigh more because of genetic factors. In comparison, the siblings who slept seven to nine hours weighed less and were less likely to be affected by any inherited obesity genes.
The researchers believe that getting enough sleep is a major
element in how much a person's body weight is influenced by any
genetic predisposition to being overweight or obese. When you're
already exercising regularly and eating right, it's good to know
that sleeping more can give you that extra push, no matter what
body issues you've inherited.
UP YOUR ENERGY
If you've gotten a good night's rest, then you're more likely to have the energy for your workout the next day. Exercise serves as the impetus for the body's adaptation process, which takes place outside of the gym. Not allowing sufficient rest means the adaptation doesn't fully happen, and you start your next workout in an already-tired state.
It may take time to become apparent, but inadequate rest will mean your fitness and weight-loss results plateau and your risk of injury increases. "If you keep yourself sleep deprived for long enough, you could end up with a case of adrenal fatigue, meaning no matter how hard you slog it out at the gym, your body's just going to keep storing fat," says Libby. "Obviously this isn't the result you want!"
The quality of your sleep counts too," she says. "So make sure you sleep in a dark room with no electronics nearby and the more hours you get before midnight, the better! Early to bed and early to rise is still the best habit to get into."