The Forgotten Key to Successful Weight Loss

If one-third of your assets depend upon the success of a particular company, you would likely monitor its progress closely. Time is also a valuable resource; we spend about one-third of our lives sleeping. How does lack of sleep contribute to the rising rates of obesity, prediabetes, and type 2 diabetes? Has it affected your weight gain or hindered your attempts at weight loss?

A Short Changed Society

One-third of Americans do not get adequate sleep.¹ If you want to lose weight, you need to get 7 to 8 hours of good-quality sleep! Two meta-analyses found that inadequate amounts of sleep, interrupted sleep, and irregular sleep–each can make us more vulnerable to obesity, prediabetes, and type 2 diabetes.^{2 3}The shorter the duration of sleep, the higher risk of developing obesity or type 2 diabetes. Why?

Sleep Deprivation Sabotages Appetite Control

Even in a healthy young man, sleep restriction leads to increased activation of brain regions sensitive to food stimuli.⁴. In other words, reduced sleep may lead to a greater propensity to overeat. In normal weight individuals, partial sleep deprivation increases the brain’s response to unhealthy food. MRI studies demonstrate that sleep deficiency significantly decreases activity in the areas of the frontal cortex and the insular cortex that helps us control appetite.^{5 6} Sleep deficiency also increases activity in other parts of the brain and makes us crave junk food and high-calorie foods.⁷

Another study found that obese women had lower sleep efficiency, ate more quickly, and spent more time eating and sleeping during the daytime hours than normal weight women.⁸ Circadian misalignment affects sleep architecture and may reduce total sleep time. Misaligned circadian rhythms also contribute to obesity, diabetes, and comorbidities of cancer and cardiovascular diseases.

Hormone Havoc

Less Melatonin: Sleep deprivation, irregular schedules, and shift work–all can interfere with obesity and the effect of the hormone melatonin. Optimal amounts of melatonin stimulate the appearance of ‘beige fat’, a type of fat cell that burns calories instead of storing them.⁹ Exposure to light at night interferes with the quality of sleep and melatonin production.

Less Growth Hormone: Deep sleep increases the production of growth hormone from the pituitary gland. Growth hormone not only improves protein synthesis in the brain, muscles, and joints but also promotes the burning of fats. The largest increases of this hormone occur before midnight with some smaller pulses in the early morning. We should also mention that obesity blunts growth hormone production.¹⁰The largest increases of this hormone occur before midnight with some smaller pulses in the early morning.¹¹

Excess Cortisol: In moderate amounts, the adrenal hormone cortisol is a marvelous anti-inflammatory agent. However, a surplus on cortisol inhibits protein synthesis, elevates blood glucose, and encourages the accumulation of visceral fat.  Excessive visceral linked to cardiac and metabolic diseases such as metabolic syndrome, non-fatty liver disease, prediabetes, and type 2 diabetes even in individuals who would not otherwise be considered as obese.^{12 13}

Missing sleep for a few hours a night increases cortisol production.¹⁴ Circadian rhythms play a significant role in regulation cortisol. Additionally, irregular hours disturb the natural rhythm of cortisol when it is high during the morning when you awake and begins falling in the late afternoon and rapidly declines before usual hours of retirement. One’s tendency to accumulate fat is greater at night when one works, sleeps, and eats irregularly.

Satiety and Appetite-Stimulating Hormones: The body makes several satiety hormones and several appetite hormones.  The satiety hormone leptin is dependent upon the quality and quantity of sleep we get.¹⁵

Partially sleep-deprived individuals have significantly lower levels of leptin. At the same time, they also have higher levels of the appetite-stimulating hormone ghrelin so consequently, there is an increase of hunger and appetite. The changes are more pronounced in obese individuals.^{16 17} Ghrelin not only increases appetite, it lowers energy expenditure as well. Just one night of acute, moderate sleep restriction at home increased food intake, feelings of hunger, and impaired regulation of blood pressure and heart rate in young overweight adults.

Thyroid Hormone: The thyroid-stimulating hormone increases production of the thyroid hormone, which regulates all metabolism—including fat metabolism in our body. Six days of partial sleep deprivation reduces e overall mean the thyroid stimulating levels (TSH) levels more than 30%. A normal pattern of TSH release reappeared when the subjects had fully recovered.¹⁸

Sleep Restriction = More Abdominal and Visceral Fat

One CAT scan study found that even in healthy, non-obese individuals, lack of sufficient sleep led to a 9% increase in total abdominal fat area and an 11% increase in abdominal visceral fat compared to control sleep. Researchers randomly assigned participants to the control (normal sleep) group or restricted sleep group during one session and the opposite during the next session, after a three-month washout period. There were no food restrictions but during the sleep restriction segment the participants consumed more than 300 extra calories per day, eating approximately 13% more protein and 17% more fat.¹⁹

Makes Calorie-Restricted Diets Less Effective

A study found that people with short sleep duration or poor sleep quality lost less fat mass, while having a 600 kcal restricted diet over 24 weeks.²⁰

Conclusions:

Sleep is an important modulator of glucose and fat metabolism. It influences the brain circuits involved in appetite. An insufficiency of either the quality or quantity of sleep predisposes one to an increased risk of obesity, prediabetes, and type 2 diabetes. What is even worse is sleep deprivation increases one’s risk for many of the comorbidities of obesity and diabetes–heart disease, stroke, hypertension, and cancer. Aim for 7 to 8 hours of good-quality of sleep. One caveat here. While sleep restriction is an independent risk factor for obesity, sleeping more than 8 hours a day also increases the risk of developing obesity and type 2 diabetes.²¹

 

1. Liu Y, Wheaton AG, Chapman DP, Cunningham TJ, Lu H, Croft JB. Prevalence of healthy sleep duration among adults—United States, 2014. MMWR 2016; 65:137–141.[↩]
2. Itani O, Jike M, Watanabe N, Kaneita Y. Short sleep duration and health outcomes: a systematic review, meta-analysis, and meta-regression. Sleep Medicine 2017. 32246–256.[↩]
3. Zhou Q, Zhang M, Hu D. Dose-response association between sleep duration and obesity risk: a systematic review and meta-analysis of prospective cohort studies. Sleep and Breathing. 2019. 231035–1045.[↩]
4. 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. Apr; 95(4):818-24[↩]
5. Ma N, Dinges DF, Basner M, Rao H. How acute total sleep loss affects the attending brain: a meta-analysis of neuroimaging studies. Sleep. 2015 Feb 1;38(2):233-40.[↩]
6. Greer S. The impact of sleep deprivation on food desire in the human brain. Nat Commun 4, 2259 (2013). https://doi.org/10.1038/ncomms3259[↩]
7. Greer S. The impact of sleep deprivation on food desire in the human brain. Nat Commun 4, 2259 (2013).[↩]
8. Corbalán-Tutau, J.A. Timing and duration of sleep and meals in obese and normal weight women. Association with increase blood pressure. Appetite Volume 59, Issue 1, August 2012, Pages 9-16[↩]
9. Zyie Xu. Elucidating the Regulatory Role of Melatonin in Brown, White, and Beige Adipocytes. Advances in Nutrition. Advances in Nutrition. Vol 11:22.[↩]
10. Hjelholt A. Growth Hormone and Obesity. Endocrinol Metab Clin North Am. 2020 Jun; 49(2):239-250.[↩]
11. Takahashi, Y. Growth hormone secretion during sleep. J. Clin. Invest., 1968, 47: 2079–2090.[↩]
12. Mongraw-Chaffin M, Allison MA, Burke GL et al. CT-derived body fat distribution and incident cardiovascular disease: The Multi-Ethnic Study of Atherosclerosis. J Clin Endocrinol Metab 2017; 102:4173–4183.[↩]
13. Britton KA, Massaro JM, Murabito JM, Kreger BE, Hoffmann U, Fox CS. Body fat distribution, incident cardiovascular disease, cancer, and all-cause mortality. J Am Coll Cardiol 2013;62:921–925. March 2020. Pages 447-460[↩]
14. Hirotsu C, Tufik S, Andersen ML. Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep Sci. 2015 Nov; 8(3):143-52.[↩]
15. Van Cauter E. The Impact of Sleep Deprivation on Hormones and Metabolism. Medscape. Nov. 10, 24. https://www.medscape.org/viewarticle/502825[↩]
16. Spiegel K., Leproult R., Van Cauter E. Impact of sleep debt on metabolic and endocrine function. Lancet. 1999; 354(9188):1435–1439.[↩]
17. Lieve T., van Egmond, et al. Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study. Obesity. Vol. 31:3. Pages 635-641. March 2023[↩]
18. Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on metabolic and endocrine function. Lancet. 1999; 354:1435-1439.[↩]
19. Covassin N, et al. Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity. J Am Coll Cardiol. 2022 Apr 5; 79(13):1254-1265.[↩]
20. Chaput JP, Tremblay A.2012. Sleeping habits predict the magnitude of fat loss in adults exposed to moderate caloric restriction. Obesity Facts 5561–566[↩]
21. Antza C, The links between sleep duration, obesity and type 2 diabetes mellitus. J Endocrinol. 2021 Dec 13;252(2):125-141.[↩]