You're eating healthily and exercising regularly, but your weight won't budge — is a lack of sleep to blame?
A study conducted by the University of Chicago adds to mounting evidence that sleep deprivation can lead to weight gain.
In the study, 10 overweight men and women lived in a sleep lab for two separate two-week periods and were given a kilojoule-restricted diet. In the first period the participants slept for 8.5 hours a night, while on the second, 5.5 hours, Reuters reported.
The dieters lost an average of 3kg in each of the conditions — but when sleeping less they lost muscle rather than fat.
"So they lost the same amount of weight, but the composition was different," senior researcher Dr Plamen Penev said.
Dr Penev and his colleagues said they can only theorise about the reasons for the muscle loss. They suggested the extra waking hours increase the need for glucose in the brain and other parts of the nervous system, which comes from breaking down the muscle.
The study was published in the Annals of Internal Medicine.
Research from Columbia University, conducted in 2004, also found that people who get at least seven hours of sleep each night have less body fat than people who sleep less.
The study revealed that people who sleep less than four hours a night are 73 percent more likely to be obese. People who get five hours are 50 percent more prone to being overweight and 23 percent for those who sleep for around six hours.
Researchers believe this is caused by an imbalance in appetite hormones leptin and ghrelin. Leptin regulates the appetite and tells the brain how much energy is available in the body and the hormone grehlin makes you want to eat. So when you don't get enough sleep, your body has too little leptin and too much ghrelin, hence making sleepy people turn to food.
Here are a few tips to find out if you're sleep deprived
- If you fall straight into a state of sleep when you hit the pillow. Normally it should take 15 to 20 minutes for a healthy person to begin sleeping at night.
- If you feel chronically tired, leaving no time or energy for exercise.
- If you feel drowsy and lethargic for a period of time through the day — most common in the mornings.
- If you're always thinking you're hungry and turning to food (or caffeine) to help keep you energised.
So while healthy eating and exercise are key to maintaining a healthy weight, at least seven hours of sleep a night is also important. Read Health & Wellbeing's tips on getting a great night's sleep.
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