Does Lack of Sleep Cause Weight Gain?


lack of sleep

Does lack of sleep cause weight gain? Sleep is an issue for many people, with over 50% of the population having irregular sleep or complaints of sleep problems. Additionally, obesity is also a problem in the UK, with 23.1% of the population classed as overweight. These two epidemics, although separate in many ways, seem to overlap in certain areas.

There have been many different papers written and studies carried out to determine the impact that lack of sleep and our sleep patterns has on our bodies. The results from these seem to point towards lack of sleep, with a poor sleep routine having a link to a poor diet and weight gain.

Metabolic Rate

Sleep deprivation has been shown to be significant in relation to our metabolic rate. As our bodies have evolved, they have come to have a high metabolic rate during eating hours, i.e. the day time. Our metabolism then slows down over the hours that our bodies deem us to be naturally asleep i.e. during the night – as we don’t eat anything when we are asleep, we do not need our metabolism to process any food.

By interrupting this cycle, and eating during the hours that we are normally asleep, and sleeping during the hours that our metabolism deems as ‘awake time’ the food we eat isn’t processed as effectively as it should be. We need to be up and moving during the hours in which we are eating, to activate our metabolism and burn off the calories we ingest. And lets face it, if you are going for a midnight snack, it would very rarely be a salad!

Therefore, to get your metabolism on track, you need to adjust your sleeping pattern to conform with natural eating times. Avoiding lie-ins (I know this one’s hard on the weekends) and making sure you do exercise during the day is paramount to getting to sleep at the right time and in turn, correlating with your metabolic rate.


When we are tired we produce more of a hormone called ‘Ghrelin’; this is a hormone produced by our bodies that reminds us to eat. Therefore, this means that sleep deprivation and hunger go hand in hand.

In addition, when we are tired our bodies lack the hormone ‘Leptin’; this hormone tells us to stop eating. This leads to a ‘Double Hit’ scenario which has been explored and commented on by Professor Matthew P. Walker from the University of California. He outlines that a sleepy brain responds more to junk food, and has less of an ability to restrain the impulse to eat.

Your brain is doing you a disservice from two different angles at once, making it extremely difficult to rein in the amount of calories you are eating when tired. Therefore, we can see why weight gain is a problem linked with tiredness, as a sleepy brain has low control over your food choices.

The Proof is in the Pudding

Our bodies crave calorific foods when we are run down or tired, as we crave ‘quick fix’ sugars that can turn into energy to keep us going. Additionally, these ‘bad foods’ boost the serotonin levels in our brain, making us feel happier psychologically. Unfortunately, a lot of the foods that we crave are high in fat, and refined sugar, which add significantly to weight gain.

When we are tired, fresh food preparation and cooking become a chore. Microwavable food and takeaways are extremely high in salt and generally a poor alternative for cooking fresh. Anyone who is watching their weight must ensure a good sleep routine is in place, as it avoids these damaging tiredness habits. Be it work or socializing that we are busy with, sleep must be a priority to be able to lead a healthy and lighter weight life.

Weight gain is something that can be avoided with healthy eating, regular exercise and sufficient sleep. A regular sleep pattern and comfort in the bedroom is key to a good night’s sleep, in turn reducing the risk of weight gain!

Contributing Author: This article was written by Danielle Bagworth, an avid lifestyle writer with a serious passion for sleep.


Carly Fraser has her BSc (Hons.) Degree in Neuroscience, and is the owner and founder at Live Love Fruit. She currently lives in Winnipeg, Manitoba, with a determined life mission to help inspire and motivate individuals to critically think about what they put in their bodies and to find balance through nutrition and lifestyle. She has helped hundreds of thousands of individuals to re-connect with their bodies and learn self-love through proper eating habits and natural living. She loves to do yoga, dance, and immerse herself in nature.


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