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Sleep DOES affect fat loss!

t has been thought that poor sleeping habits will not help with performance but what about fat loss?

Key hormones that stimulate muscle building and recovery are released during good quality sleep being Growth Hormone and Testosterone but hormones that [promote hunger are also released when there is not enough sleep. Ghrelin is a hormone that promotes hunger prior to a meal and Leptin tells you your full after a meal. As the study suggests below ghrelin does effect fat loss and Leptin (promotes satiety) appears not to perform as it should when Ghrelin levels are higher leaving people hungry after meals. It is important to note here that hormones are powerful chemical messengers and our intentions maybe the best but controlling your hormones will allow for the correct behaviour. A tough but capable task to be aware of.

The following is a study by a team at the University of Chicago get interesting.

Firstly, the researchers, led by Plamen Penev, assistant professor of medicine at the university, found that when individuals who were dieting got a full night’s sleep, they lost the same amount of weight as when they slept less. The interesting part of the findings came next, when the researchers gauged that a full night’s sleep was associated with more than 50 per cent of their weight loss coming from fat. This compared favourably to only a quarter of weight loss coming from fat when they did not get a full night’s sleep.

Additionally, when sleep was restricted, dieters felt hungrier – making a good sleep doubly important; ‘If your goal is to lose fat, skipping sleep is like poking sticks in your bicycle wheels. Cutting back on sleep, a behavior that is ubiquitous in modern society, appears to compromise efforts to lose fat through dieting. In our study it reduced fat loss by 55 percent’ said Plenev.

For the study, 10 overweight or obese volunteers were placed on restricted diets whereby they consumed 90 per cent of the calories necessary to maintain their weight without the use of physical activity.

Firstly, they were studied for two weeks in a laboratory setting when they were able to sleep for a longer time, averaging 7 hours 25 minutes. Secondly, they were studied in the same circumstances for two weeks but with an average sleep time of only 5 hours 14 minutes.

In each of the two stages of the study, the participants lost an average 3kgs. In the full sleep period, 1.4kg of this was fat (with the rest being mostly protein). In the restricted sleep period, only 590grams of the weight lost was fat.

When sleep deprived, the dieters also developed increased levels of the hormone ghrelin, which stimulates hunger, reduces energy expenditure and promotes fat retention; ‘In our experiment, sleep restriction was accompanied by a similar pattern of increased hunger and … reduced oxidation of fat’ the researchers noted.

Although a link between sleep and weight has been drawn previously, this research provided clearer findings; ‘For the first time, we have evidence that the amount of sleep makes a big difference on the results of dietary interventions. One should not ignore the way they sleep when going on a diet. Obtaining adequate sleep may enhance the beneficial effects of a diet. Not getting enough sleep could defeat the desired effects’ said Penev.

Source: Annals of internal medicine

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