By Dayne Hudson

We're told how important sleep is for growth, but what effect does it have on our abs?

Recent research looked at answering this question, using data from 30 Greek women from the ages of 30-60 and examining them for 7 days (1).

They found that body fat percentage decreases by 2.8% for each hour a day more sleep the subjects got. The researchers concluded:

"Therefore, the shorter the sleep duration, the greater is the body fatness."

Check out the graph below - it shows the fat percentage of one woman and her subsequent number of hours sleep she got per day.

An hour more sleep reduces fat percentage by three percent

More Sleep For More Fat Loss?

Now of course, this is just an observational study and with a small group of people, and therefore shouldn't be taken as gospel. But it's still interesting regardless!

The researchers suspect that a lack of sleep leads to an increase in the production of a hormone that stimulates ghrelin (your appetite hormone), and decreases the production leptin (your appetite supression hormone).

This notion also been supported in further research.

A year later, more research was conducted into this ideology - this time into sleep duration and fat intake (2).

Data from 2828 adults living in China was examined, with researchers finding "an association between decreased sleep duration and increased fat intake in humans."

Their results found a statistically significant association between time spent asleep and fat and carbohydrate intake.

And subjects who slept less than 7 hours per day had a significantly higher fat intake than those who slept for 7-9 h per day (2).

But not all research into this area has been the same - those who slept less in this study (3), didn't actually consume anymore calories than those who slept more.

Sleeping And Weight Loss - What's The Verdict?

So it seems as if the answer to this question warrants more research, and it isn't all that cut and dry. However, shooting for 8 hours of sleep seems to still be the recommendation. 

Whilst getting more sleep does seem to be better for fat loss we're still not 100% certain. But with less sleep being detrimental to us in many different ways, sleeping for longer should still be your aim even without fat loss in mind.

At this stage, sleep more to favour a potential benefit for fat loss, with a whole host of other things too!

 

"Stay Fit, Stay Flexed!"

 

REFERENCES

(1) Rontoyanni VG, Baic S, Cooper AR. Association between nocturnal sleep duration, body fatness, and dietary intake in Greek women. Nutrition. 2007 Nov-Dec;23(11-12):773-7. Epub 2007 Sep 20.
 
(2) Shi Z, McEvoy M, Luu J, Attia J. Dietary fat and sleep duration in Chinese men and women. Int J Obes (Lond). 2008 Dec;32(12):1835-40. doi: 10.1038/ijo.2008.191. Epub 2008 Nov 4.
 
(3) Kant AK, Graubard Bl. Association of self-reported sleep duration with eating behaviors of American adults: NHANES 2005-2010. Am J Clin Nutr. 2014 Sep;100(3):938-47. doi: 10.3945/ajcn.114.085191. Epub 2014 Jul 23.

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