How lack of sleep makes us gain weight #97
Poor sleep and our metabolism
Hello lovely people,
We might eat 250- 385 more calories daily when we don’t sleep well. But why?
Today, I want to discuss how sleep affects our metabolism.
Top 3 insights from this article:
1️⃣ When we don’t sleep, we burn more calories during the night, circa 100kcal more
2️⃣ Our hunger and satiety hormones, leptin and ghrelin, overcompensate the next day, increasing our hunger
3️⃣ Activity in reward regions of the brain increases, making us crave more junk food
Hunger
While we peacefully sleep in our beds, we use much less energy than when we are awake. There is no surprise there. Our body still uses some energy for the repair work it must do.
However, when we don’t get enough sleep - anything under 7 hours - we burn more calories as the body needs to maintain more body functions when you are awake. This extra expenditure is approx. 100 extra calories. It doesn’t seem much in the grand scheme.
This extra energy expense catches the eyes of our hunger and satiety hormones: leptin and ghrelin. They determine when we are hungry and govern our eating behaviour. The energy expense makes us hungrier the next day to compensate, so we eat more, between 250- 385 calories more. Our body doesn’t like to spend more than it consumes. It puts our chance of survival in times of famine at risk. It has powerful mechanisms to make sure you not lose weight.
This is why losing weight has little to do with willpower and discipline. You are pretty much fighting your genetics.
These numbers don’t seem like much, but let’s add things up. Let’s assume that over 2024, we’ve had 45 nights of bad sleep (around 3-4 nights/month).
That will equal an excess of 6,750kcal. And this is only from bad sleep, we won’t consider other things that lead to excess calories throughout a year. It takes about 7000kcal to put on 1kg. You can see how not sleeping well, year by year, makes us accumulate weight.
Studies found that short sleep durations, defined as less than 5 or 6 h per day is associated with a 38% absolute increase in obesity compared with normal sleep duration. We know PCOS is worsened by weight gain. Sleep is one of the things we need to pay attention to when managing PCOS.
High-calorie foods
In addition to this extra energy, sleep restriction can increase the activity of brain regions linked to reward and desire for high-calorie foods, so we end up eating more junk. Specifically, insufficient sleep was reported to increase the consumption of high-carbohydrate foods, fats, sugar-sweetened beverages and alcohol. In addition, it creates an increased drive to eat for pleasure rather than need.
Insulin levels
Sleep loss, both in duration and quality, can lead to decreased insulin sensitivity. A study showed that restricting sleep to four hours per night for five nights decreased glucose tolerance by over 40%.
This is very relevant for PCOS. Insulin resistance is one of the main causes of our annoying symptoms, and we don’t want to add another cause. This is why managing PCOS needs to be holistic, ensuring we build a routine that is advantageous for our condition.
I will delve deeper into the relationship between sleep and PCOS next Sunday.
See you,
Francesca
Francesca is a Nutritional Therapist with years of experience managing PCOS symptoms. If you are interested in one-to-one consultations, you can book a free discovery call here.
References
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Fernandez, R. C., Moore, V. M., Van Ryswyk, E. M., Varcoe, T. J., Rodgers, R. J., March, W. A., Moran, L. J., Avery, J. C., McEvoy, R. D., & Davies, M. J. (2018). Sleep disturbances in women with polycystic ovary syndrome: prevalence, pathophysiology, impact and management strategies. Nature and Science of Sleep, 10, 45–64. https://doi.org/10.2147/NSS.S127475
Hung, J.-H., Hu, L.-Y., Tsai, S.-J., Yang, A. C., Huang, M.-W., Chen, P.-M., Wang, S.-L., Lu, T., & Shen, C.-C. (2014). Risk of psychiatric disorders following polycystic ovary syndrome: a nationwide population-based cohort study. PloS One, 9(5), e97041. https://doi.org/10.1371/journal.pone.0097041
Johnson, D. A., Billings, M. E., & Hale, L. (2018). Environmental determinants of insufficient sleep and sleep disorders: Implications for population health. Current Epidemiology Reports, 5(2), 61–69. https://doi.org/10.1007/s40471-018-0139-y
Saghir, Z., Syeda, J. N., Muhammad, A. S., & Balla Abdalla, T. H. (2018). The amygdala, sleep debt, sleep deprivation, and the emotion of anger: A possible connection? Cureus, 10(7), e2912. https://doi.org/10.7759/cureus.2912
Walker, M. (2018). Why we sleep: The new science of sleep and dreams. Penguin Books.
Disclaimer: We are all unique in our ways, so this information is for educational purposes only. In my communications, I summarise research data and bring my experience. This shouldn’t be viewed as medical advice at any point. Please consult your healthcare provider further about your health needs.