The link between sleep and obesity has already been recognised for some time. However, new research shows that it’s potentially much more complicated than was previously thought.
Does lack of sleep affect your appetite?
Sleep is an important part of regulating two ‘hunger hormones’, leptin and ghrelin. Leptin is made in the fat cells of the body, and suppresses feelings of hunger as well as increasing insulin sensitivity. Ghrelin is leptin’s opposite – made mainly in the gut it promotes the feeling of hunger.
Too little sleep (less than 8 hours a night) disrupts the levels of these hormones. Leptin levels fall, and ghrelin levels are raised, resulting in increased hunger and food intake.
Couldn’t I just use willpower?
That’s very difficult in this instance. Partly it’s because it’s not just you fancying a biscuit with a cup of tea, or eating a snack out of habit. It’s the hormones in your body sending you a very powerful and compelling message that you simply have to eat. Given the fact that the lack of sleep will also affect your reasoning and judgement, you’re very unlikely to get past this using willpower.
In fact, research shows that people whose hunger is linked to lack of sleep are likely to opt for higher calorie food than normal, and to consume larger portions.
Is there any other link between sleep and obesity?
There is now research showing that lack of sleep doesn’t just affect appetite. It affects our metabolism, and the way that the body stores fat. Even in healthy people, after missing one night’s sleep their fat cells were more likely to absorb lipids, and to reproduce as well. The link between sleep and obesity is even more fundamental that was first thought.
Can’t I exercise my way out of this increased fat?
Unfortunately, muscle is also adversely affected by a lack of sleep. It reduces the levels of proteins essential in maintaining and building muscle mass. Not only will this make exercise more difficult, so will the increased inflammation that comes from lack of sleep – and which is also a risk factor for Type 2 diabetes.
If it’s not willpower and exercise what is the way round this?
Quite simply the role of sleep is irreplaceable, and a lack of it can’t be made up for by other efforts. Good sleep hygiene, a consistent sleep routine, and 8 hours sleep a night are the only real answers.
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