Isn't sleep wonderful? Yes, when you can get it! Obviously we feel better - and even look better - when we've had a good night's kip, but are you aware of how sleep affects your ability to lose weight?

Poor sleep makes you crave the wrong foods

When you don't get enough sleep, it causes a spike in your cortisol (stress hormone) levels. Cortisol is also the pesky hormone that triggers the brain's reward centres, which make you crave unhealthy foods. Poor sleep also makes your body produce higher levels of ghrelin, the hormone that stimulates hunger, and lower levels of leptin, the hormone that tells you you're full. Crazy stuff, huh?

Metabolic grogginess

University of Chicago researchers looked into what happens in the body after four days of poor sleep. They determined that even this kind of sleep deprivation can play havoc with your fat cells! Within those four days, there is marked disruption in the way your body uses insulin. As a matter of fact, insulin sensitivity drops by over 30 percent! Why is that bad? Well, when your insulin is working as it should, fatty acids and lipids are removed from your blood stream and eliminated. When it's not, the excess insulin stores fat in the wrong parts of your body, like your liver. Eventually, down the track, diabetes becomes a risk.

So it's not just because you're tired and dragging your feet that makes you reach for that chocolate bar or bag of chips. There's a whole hormonal dance going on inside you that you're not aware of. That means you don't have to feel guilty about caving to cravings, and you also know there's something you can do about it ... SLEEP!