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Can Inadequate Sleep Increase Body Fat?

Learn about how adequate amounts of sleep can affect your hunger hormones.
Written by
Ellie Tarence Hiller
Published on
Jan 2, 2024

Can Inadequate Sleep Increase Body Fat?

Main Takeaway: If you want to significantly increase your rate of success in healthy eating habits, then consistently get 8 hours of sleep per night.

Question: Do you plug your iPhone up every night before you go to sleep?

I hope you answered yes, because we all know a dead phone offers nothing to us in return.

One of the highest functioning handheld devices is rendered absolutely useless if it is not charged.

In the exact same way, your body has a finite amount of battery power each day. If it is not recharged, you are starting the next day at a deficit, and can run out far sooner as the day progresses.

Your body will find ways to conserve the battery power it does have by compromising efficiency in important functions like digestion, mental clarity, and even your mood and decision making.

Think “low power mode” on your phone. Where the screen shuts off within what feels like 0.3 seconds. The background light dims, wifi scanning pauses, the “hey siri” function is disabled, etc. It’s quite annoying really. The phone isn’t operating at its highest potential.

In a sleep deprived state, your body operates in "low power mode."

How is this related to nutrition?

As  it pertains to nutrition, the effect on your decision making processes is most significant.

Each food you choose to put in your mouth is a decision. Whether it is a mindless or intentional decision, it is a decision nonetheless.

Each decision has an effect. Once it hits your body, your body is now responsible for absorbing, digesting, and eventually getting rid of it as waste.

Your body has some incredibly fascinating influences on your food choices in the form of hormones. Two of the most influential hormones related to our food choices are called leptin and ghrelin.

Your body will find ways to conserve the battery power it does have by compromising efficiency in important functions like digestion, mental clarity, and even your mood and decision making.

So what are these hunger and satiety hormones?

Ghrelin is commonly referred to as the “hunger hormone.” It plays a large role in communicating with your hypothalamus that you need food (aka it stimulates your appetite.)

When you think of ghrelin think of “growling.” Your stomach and small intestine are the primary organs that secrete ghrelin. Your plasma ghrelin levels are typically highest before a meal when you haven’t eaten in a while.

Basically your enteroendocrine system secretes a hormone to tell the decision making center in your brain (hypothalamus) that you need calories and energy.

Leptin is the hormone that tells your brain “I am full.” When you think of Leptin think Limit. Your body is attempting to limit food intake by telling you it’s full.  

Leptin is fascinating because it has a direct relationship with an individual’s body fat percentage.

Adipose cells (fat cells) release leptin. SO…. the higher the body fat of an individual, the higher the leptin levels will be. Your body is telling you it doesn’t need more energy.

In summary, it all comes back to homeostasis and maintaining energy balance in your body. In very simple terms, if your body needs energy, it tells you to eat by stimulating hunger. If your body doesn’t need more energy, it tells you it is satiated so you can stop eating.

These two hormones communicate with our hypothalamus in our brains to maintain energy balance in our body.

How are these hormones related to sleep?

Inadequate sleep has been shown to increase ghrelin levels and decrease leptin levels.

First of all, what exactly is “inadequate sleep?”

According to the study by Taheri S. et al (2004),  the individuals with "inadequate sleep" slept less than 8 hours.

The findings revealed that the  participants who had < 8hrs of sleep had reduced leptin levels and elevated ghrelin levels which can lead to overeating.

The study revealed an increase in body mass index in the individuals who sleep less than eight hours and had the higher plasma ghrelin levels.

This result suggests that the effect sleep has on leptin and ghrelin levels contributed to the increase in BMI in the individuals who were sleep deprived.

In clearer terms, sleep deprivation resulted in hormone levels that signaled to their brain they are hungrier than normal (increased ghrelin = increased appetite). Sleep deprivation also tempered the body’s ability to recognize satiation (when it is full). Decreased levels of leptin = decreased ability to recognize when the body is satisfied.

It is reasonable to conclude that sleep deprived individuals are more likely to have troubles with proper nutritional choices and sticking to a plan.

Who wants their hormones working against them?

The answer is to get more sleep. Have your hormones work in harmony with your goals not against them.  

Action Step: Be intentional about getting 8 or more hours of sleep per night.


1. 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 Medicine. 2004;1(3):e62. doi:10.1371/journal.pmed.0010062

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