If you’re like me, you often stay up too late at night and realize how much of a mistake that was the next morning… only to repeat the same mistake again that night.
Sleep is obviously very important for overall health, but it plays significant roles in fat loss as well. Rest is essential to grow and maintain your muscles and regulate your energy properly. You can work like crazy to manage a caloric deficit with diet and exercise, but if you aren’t prioritizing sleep, you may be shooting yourself in the foot from a fat loss perspective (even if you are losing weight!)
In a study by Nedeltcheva et al, subjects were placed on similar caloric restrictions and assigned to 14 days of either 5.5 hours of sleep per night or 8.5 hours of sleep per night. The groups lost similar amounts of weight (approximately 6-7 pounds), but for the 5.5-hour group, only a quarter of this weight loss was fat, as compared to more than half of the weight lost as fat in the 8.5-hour group.
Not getting enough sleep obviously makes your body more fatigued, but the effects are farther reaching as this can subconsciously decrease your NEAT (non-exercise activity thermogenesis) and lead to diminished performance in the gym. This is counter-productive when you’re trying to maintain a calorie deficit! Higher levels of ghrelin in the body can lead to preferential preservation of fat and use of lean body mass for energy instead. This may be related to muscle being more “expensive” energy-wise for the body to maintain. All of these factors can set you up for weight regain after you’ve finished your dieting phase.
As you can see, inadequate sleep can mess with both your energy intake and your energy expenditure. Even short term sleep restriction of a couple of days can have these detrimental effects. It can be difficult to keep up with all of life’s obligations while trying to make time for the gym, but try not to skimp on sleep!
-Katy Hair, RD, LDN, CPT
Nedeltcheva, AV, et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010 Oct 5; 153(7): 435-441.