The sleep diet
If you go on a diet where you will restrict how much you eat then you will probably lose weight. The bad news is that if you are not getting enough sleep the weight that you lose will not be fat, it will be muscle.
Almost all animals sleep. That includes mammals, birds, fish, amphibians and most reptiles. From this mere fact you can guess that sleep is a fairly successful behavioural strategy in evolutionary terms. Sleep happens as a result of a complex interplay between hormones in your body and lots of regenerative things happen while your eyes are shut and your consciousness escapes to another dimension. It is hardly surprising then that if you do not get enough sleep then things start to go wrong and that also applies to how you metabolise fat.
In a new study healthy adults were put on a kilojoule restricted diet and were randomly assigned to sleep either 5.5 or 8.5 hours per night for a period of two weeks. The researchers measured loss of fat and lean body mass and found that those people who slept 8.5 hours per night lost 56 per cent more body fat than those who slept only 5.5 hours.
By contrast the shorter sleepers lost almost twice as much muscle mass as those who were getting a good rest. So if you were going solely by what the scales were telling you, since muscle weighs more than fat, you might not even be aware of the damage that lack of sleep was doing to your weight loss attempts.
The researchers found that lack of sleep caused an increase in a hormone called ghrelin in the blood. Ghrelin reduces energy expenditure, stimulates hunger, promotes retention of fat, and increases glucose production in the body.
Thereâ€™s your prescription for weight loss then: get a good nightâ€™s sleep. For all you parents out there who have suffered years of interrupted sleep raising children, if those offspring should ever question your physique you could with some justification respond, â€œYou turned me into this!â€. See, thereâ€™s always a bright side.