Do you have a healthy diet? Are you exercising regularly? Are you getting sufficient rest and sleep? Enjoying work? Not stressing? Maintaining healthy relationships with family, friends, and co-workers?
All of the components above contribute to a healthy, happy life. They also influence each other in a number of different ways. If you, for example, enjoy work, then you’re probably less stressed; and if you exercise regularly, you probably try to eat healthily to maximize your results.
Sleeping well makes you feel more rested and helps you to exercise better. What you probably don’t know though, is that sleep can actually increase hunger and appetite. There’s a known correlation between lack of sleep and obesity, and an increase in appetite could be one of the reasons why.
A randomized crossover study from 2017 (Hibi et al., 2017) investigated the effects of 3 nights with either 7 hours of sleep or 3.5 hours of sleep on hunger, energy expenditure, core body temperature, and different hormones, in nine young (around 23 years old) normal weight men.
They found an increase in hunger (based on a questionnaire) and a decreased fullness score when participants had only 3.5 hours of sleep as compared to participants who had 7 hours of sleep. There was no difference in energy expenditure between the different sleeping conditions (measured by whole-room indirect calorimeter), but the blood test showed a decrease in a hormone, PYY, linked to reduced appetite. When participants slept for only 3.5 hours, they had a slightly lower core body temperature, which could be attributed to a disturbance of the body’s normal daily rhythm, the circadian rhythm.
In short, the study showed that 3 nights of sleep restriction increased hunger, and decreased fullness, despite energy expenditure staying the same. This is a bad combination if you’re trying to lose weight or at least avoid weight gain.
Thus it appears that a lack of sleep not only makes you feel sluggish and tired, but could also affect your diet progress by increasing your appetite and hunger.
Sleeping less also gives you more time to eat (but also more time to be active). An interesting anecdote, cyclists trying to lose weight before a tough race (to have less mass to carry in the mountains) sometimes go to bed straight after training to combat hunger feelings from being in a calorie deficit. This way they avoid experiencing the food cravings after training due to being asleep (of course we are not suggesting you do this, as this isn’t a healthy way to lose weight and keep it off for the long term).
In the end, there are a lot of factors that contribute to a healthy life, many of which affect each other synergistically. Improving one factor, like sleep, many times improves other health promoting factors.
Unfortunately, it’s not always possible to get the sleep that you want and require, sometimes life is just too busy. That being said, simply by being aware that you might be hungrier when sleep deprived can help you plan ahead, and be prepared. If you are prone to snacking, for example, a few nights with less sleep might increase your likelihood of this behaviour, so having access to healthy snacks can help you improve the chances of sticking to your diet. You could also just prepare yourself by accepting that it will be harder to stick to your diet, and avoid snacking/eating unhealthily that day.
So, use knowledge to your advantage.
Fredrik Wernstål is a final year medical student with a passion for nutrition, training, performance, and health. His goal is to help people reach a healthier and happier life by providing research-based advice.
Hibi, M., Kubota, C., Mizuno, T., Aritake, S., Mitsui, Y., Katashima, M., Uchida, S., 2017. Effect of shortened sleep on energy expenditure, core body temperature, and appetite: a human randomised crossover trial. Sci. Rep. 7, 39640. doi:10.1038/srep39640
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