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Sleep Loss: Why It’s Making You Fat

How will do you sleep?

sleep hormone As children, we never think about something as simple as sleep. We wake up in the morning, full of energy, and fall asleep soundly at night, with no problems to waver us from our slumber.

However, as we age, many problems get in the way of a good night’s rest. Besides the startling fact that sleep loss is cumulative,1 chronic sleep debt results in vast changes of neuro-behavior.2 Furthermore, individuals that believe they ‘adapt’ to sleep loss are only fooling themselves.3

Deficits in daytime performance due to sleep loss are experienced universally and associated with a significant social, financial, and human cost.4 If you sleep 6 hours or less per night, chronically, it is the same as staying awake for 2 days, neurologically.5 And on top of all that, sleep loss helps makes you fat.6

So what is going on in your body, when you are sleep deprived?

And how does this stream of biochemical changes help to make you fat?

To start with, research shows sleep deprivation has profound metabolic and cardiovascular implications.7

Hormonally and biochemically, we point the finger of blame at two suspects: leptin and ghrelin.

These two hormones have a profound effect on appetite control.8 And these two hormones are both greatly affected by sleep loss.9,10

In a single night of sleep loss, men experience an increase in levels of ghrelin, which is usually referred to as your ‘hunger’ hormone.11 Your ‘satiety’ hormone, leptin, by contrast, is decreased after sleep loss.12 So you will be hungrier, and less satisfied when you eat. Not only that, but your nucleus accumbens, which is your brain’s pleasure center, and a whole host of other brain areas, such as the putamen, thalamus, insula, and prefrontal cortex, are more susceptible to food reward, when sleep deprived.13

Neurons that release serotonin, are modified via carbohydrate ingestion.14 Since 5-Hydroxytryptamine (5-HT), or serotonin, is a vital neurotransmitter, which helps to regulate sleep,15 the biochemical parallels between diet, specifically carbohydrate intake, and sleep, can be further filled in.

The neurological differences between a meal filled with protein, and a meal filled with carbohydrate, are vast and surprising.

Your brain actually utilizes the food-induced changes in brain serotonin in order to make choices about what to eat.16

You can begin to see how this would also cause you to crave carbohydrates, especially when sleep deprived.17 Your brain is receiving less of a satiety signal, more of a hunger signal, is fatigued, and carbohydrates provide a quick boost of energy.18 This then disrupts your next meal, and possibly your sleep.19

Furthermore, studies have shown that glucagon-like peptide 1, which is a hormone that promotes satiety, is delayed in doing its job, when sleep deprived.20 This is yet another biochemical mechanism by which you can overeat, when you’re not well rested. Add to that list, neuropeptide Y. Neuropeptide Y normally expresses itself in order to increase food intake.21

When sleep deprived, this neuropeptide expression rapidly increases,22 effectively telling your brain to eat more.

More and more studies are showing the link between sleep deprivation and obesity.23

There are even interesting studies relating nighttime eating and weight gain.24

A simple search for the terms ‘sleep and obesity’ yields over 6000 results in one scientific database alone.5

The link is very clear, and many of the biochemical mechanisms are outlined above.

A real food based approach, like The Paleo Diet, not only provides a plethora of nutrients, minerals and vitamins, but helps to stabilize blood sugar levels, and regulate hormones.26

This not only means that you’ll sleep better, but, as a result, it will be much easier to stay lean, fit and healthy.


Casey Thaler, B.A., NASM-CPT, FNS

Casey Thaler, B.A., NASM-CPT, FNS is an NASM® certified personal trainer and NASM® certified fitness nutrition specialist. He writes for Paleo Magazine® and for PaleoHacks. He also runs his own nutrition and fitness consulting company, Eat Clean, Train Clean®. He is pursuing his Ph.D in Nutritional Biochemistry, hopefully from Harvard University.


1. Cohen DA, Wang W, Wyatt JK, et al. Uncovering residual effects of chronic sleep loss on human performance. Sci Transl Med. 2010;2(14):14ra3.

2. Dinges DF, Pack F, Williams K, et al. Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night. Sleep. 1997;20(4):267-77.

3. Cohen DA, Wang W, Wyatt JK, et al. Uncovering residual effects of chronic sleep loss on human performance. Sci Transl Med. 2010;2(14):14ra3.

4. Durmer JS, Dinges DF. Neurocognitive consequences of sleep deprivation. Semin Neurol. 2005;25(1):117-29.

5. Van dongen HP, Maislin G, Mullington JM, Dinges DF. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep. 2003;26(2):117-26.

6. Jean-louis G, Williams NJ, Sarpong D, et al. Associations between inadequate sleep and obesity in the US adult population: analysis of the national health interview survey (1977-2009). BMC Public Health. 2014;14:290.

7. Sharma S, Kavuru M. Sleep and metabolism: an overview. Int J Endocrinol. 2010;2010

8. Klok MD, Jakobsdottir S, Drent ML. The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Obes Rev. 2007;8(1):21-34.

9. Knutson KL. Impact of sleep and sleep loss on glucose homeostasis and appetite regulation. Sleep Med Clin. 2007;2(2):187-197.

10. Motivala SJ, Tomiyama AJ, Ziegler M, Khandrika S, Irwin MR. Nocturnal levels of ghrelin and leptin and sleep in chronic insomnia. Psychoneuroendocrinology. 2009;34(4):540-5.

11. Schmid SM, Hallschmid M, Jauch-chara K, Born J, Schultes B. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res. 2008;17(3):331-4.

12. Taheri S, Lin L, Austin D, Young T, Mignot E. Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Med. 2004;1(3):e62.

13. St-onge MP, Mcreynolds A, Trivedi ZB, Roberts AL, Sy M, Hirsch J. Sleep restriction leads to increased activation of brain regions sensitive to food stimuli. Am J Clin Nutr. 2012;95(4):818-24.

14. Wurtman RJ, Wurtman JJ. Brain serotonin, carbohydrate-craving, obesity and depression. Obes Res. 1995;3 Suppl 4:477S-480S.

15. Jing F, Zhang J. Metabolic Kinetics of 5-Hydroxytryptamine and the Research Targets of Functional Gastrointestinal Disorders. Dig Dis Sci. 2014;

16. Wurtman RJ, Wurtman JJ. Carbohydrate craving, obesity and brain serotonin. Appetite. 1986;7 Suppl:99-103.

17. Nedeltcheva AV, Kilkus JM, Imperial J, Kasza K, Schoeller DA, Penev PD. Sleep curtailment is accompanied by increased intake of calories from snacks. Am J Clin Nutr. 2009;89(1):126-33.

18. Weiss A, Xu F, Storfer-isser A, Thomas A, Ievers-landis CE, Redline S. The association of sleep duration with adolescents’ fat and carbohydrate consumption. Sleep. 2010;33(9):1201-9.

19. Ip M, Mokhlesi B. Sleep and Glucose Intolerance/Diabetes Mellitus. Sleep Med Clin. 2007;2(1):19-29.

20. Benedict C, Barclay JL, Ott V, Oster H, Hallschmid M. Acute sleep deprivation delays the glucagon-like peptide 1 peak response to breakfast in healthy men. Nutr Diabetes. 2013;3:e78.

21. Ramos EJ, Meguid MM, Campos AC, Coelho JC. Neuropeptide Y, alpha-melanocyte-stimulating hormone, and monoamines in food intake regulation. Nutrition. 2005;21(2):269-79.

22. Koban M, Le WW, Hoffman GE. Changes in hypothalamic corticotropin-releasing hormone, neuropeptide Y, and proopiomelanocortin gene expression during chronic rapid eye movement sleep deprivation of rats. Endocrinology. 2006;147(1):421-31.

23. Spivey A. Lose sleep, gain weight: another piece of the obesity puzzle. Environ Health Perspect. 2010;118(1):A28-33.

24. Gluck ME, Venti CA, Salbe AD, Krakoff J. Nighttime eating: commonly observed and related to weight gain in an inpatient food intake study. Am J Clin Nutr. 2008;88(4):900-5.

25. sleep and obesity – PubMed – NCBI. (n.d.). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/?term=sleep+and+obesity

26. Frassetto LA, Schloetter M, Mietus-synder M, Morris RC, Sebastian A. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr. 2009;63(8):947-55.