While the term “beauty sleep” is widely used, maybe a new term should be used: “diet sleep”. It seems that sleep is one of the major elements which influences how we gain or lose fat. Lack of sufficient sleep, can lead you to gain weight faster or lose it more slowly than you would have done otherwise.
In this article I want to go over some of the reasons why sleep helps weight loss (and fat loss) and what do studies of the matter have to say.
There are 3 main reasons why short sleep duration may cause you to gain weight:
- Short sleep time boosts your appetite – This is something that I’ve covered in a separate article which you can read here: Lack of sleep increases appetite. The research is quite clear: when you don’t get enough sleep, you are hungrier the next day. In some cases this hunger is focused on high calorie, high carbs food, often not the foods you want to eat when trying to lose weight.
- Lack of sleep leads to an increase in stress and in the “stress hormone”, Cortisol . This is a hormone which is known to be connected to an increase in abdominal fat storage which is why sleep may be a primary weapon in the fight against belly fat.
- Short sleep leads to a reduction in activity and energy expenditure. This stands to reason as the less sleep you get the more tired you are and the more tired you are the less inclined you are to exercise and burn more calories through activity.
Sleep and Weight Loss – What Does the Research Say
Let’s look at some examples of studies which were done to investigate the effect of sleep on weight gain and weight loss.
The first one is a study which was published in the International Journal of Obesity in March, 2011 . In this study, 472 people were put on a regimen which included calorie restriction and physical exercise. At the end of the study there were a number of clear conclusions including two which should be noted here:
- Those who slept more succeeded with the diet and fitness plan more.
- Those with lower stress (which is connected with sleep duration), lost more weight than the other examinees.
What we can clearly see is that sleep time is a major factor in the success or failure of a diet plan and it influences the results you may achieve with it.
Lack of sleep acts like a two-pronged attack on the calorie deficit you need to achieve for weight loss. It makes you hungrier so you consume more calories and it lowers the number of calories you burn through activity . This is why lack of sleep is a major factor of the success of any weight loss plan: whether it’s based on correct eating, on fitness, or on both.
Sleep is also important at a time when many women most struggle with their weight: after delivering a baby. Post pregnancy weight loss is often a big challenge as women face greater responsibility, less free time, and physical issues due to the delivery. As a study done by the Kaiser Permanente Research Foundation shows , lack of sleep in women after pregnancy is directly related to weight retention 1 year after delivery. Basically, if you want to lose the baby weight, make sure to get some sleep.
Sleep Loss and Fat Loss
Finally we come to the point of fat loss. After all, most of us don’t want to merely lose weight, we want to burn more body fat. We want the pounds we shed to be made up of fat.
In a study done by the University of Chicago Medical Center, 10 men were examined under conditions of a strict diet. The men were divided into 2 groups with one allowed to sleep longer hours than the other.
At the end of the study it was found that all the men lost a similar number of pounds. However, those who slept more lost more fat. More of their weight loss was made up of fat than was the case in those who had inadequate sleep. This is a classic case of weight loss vs. fat loss and sleep is a main factor.
Proper sleep is important for anyone who wants to lose weight and body fat. There is growing evidence of the connection between lack of sleep and weight gain and obesity among adults and children. Sleep has many health benefits apart from weight loss so this isn’t the only reason to make sure you’re getting enough of it. I hope it’s just an added motivation to close the TV and the computer and to go to bed a little bit earlier than usual.
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2. Elder CR, Gullion CM, Funk KL, Debar LL, Lindberg NM, Stevens VJ. Impact of sleep, screen time, depression and stress on weight change in the intensive weight loss phase of the LIFE study. Int J Obes (Lond). 2011 Mar 29
3. Knutson KL, Spiegel K, Penev P, Van Cauter E. The metabolic consequences of sleep deprivation. Sleep Med Rev. 2007 Jun;11(3):163-78. Epub 2007 Apr 17.
4. Gunderson EP, Rifas-Shiman SL, Oken E, Rich-Edwards JW, Kleinman KP, Taveras EM, Gillman MW. Association of fewer hours of sleep at 6 months postpartum with substantial weight retention at 1 year postpartum. Am J Epidemiol. 2008 Jan 15;167(2):178-87. Epub 2007 Oct 29.