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September 11, 2020

How Sleep Affects Weight Loss

If your goal is to lose weight and become “internally fit,” skipping sleep is like trying to find your way through a maze with a blindfold on.

By Kristen Holmes

Sleep, Weight Loss and Metabolic Health

Sufficient, consolidated, quality sleep is so significant that you could easily argue it’s the most influential factor in enabling metabolic health and achieving the body you desire. If you want to feel better about your body, the most common advice is to “eat less and move more.” This suggestion is an oversimplification and perhaps not the best way to think about addressing complexities associated with internal fitness or metabolic health.

What is Metabolic Health?

As new scientific discoveries suggest, sleep may actually be the platform upon which other health improvements, like metabolic health and physical exercise, are made possible.

“Metabolic health” is commonly defined by having ideal levels of blood sugar, triglycerides, high-density lipoprotein (HDL) cholesterol, blood pressure and waist circumference, without using medications.

Sleep and Health on a Larger Scale

Through observations in WHOOP data, we can safely hypothesize that meeting sufficient sleep need and stabilizing sleep/wake times (maintaining your circadian rhythm) is one of the easiest ways to positively influence your health.

While any kind of health intervention must overcome barriers in order to achieve a meaningful impact, sleep offers a simple path to the internal synchronization necessary to optimize our mental, physical and emotional well-being.

The value of sleep vs other forms of behavior change:

  • Sleep is a low-cost (only our time) health intervention that is accessible to everyone
  • It occurs during the portion of the day (at night) when competition for our time and attention is greatly reduced
  • An improvement to sleep is not changing behavior, at worst it is simply a modification to existing behavior (everybody sleeps!)

There is a rising wave of external research that also illustrates the critical contribution of sleep towards our greater health. As Dr. Matthew Walker, author of Why We Sleep and the Founder and Director of the Center for Sleep Science at the University of California, Berkeley, makes clear in no uncertain terms:

“A balanced diet and exercise are of vital importance, yes. But we now see sleep as the preeminent force in this health trinity. The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. It is difficult to imagine any other state—natural or medically manipulated—that affords a more powerful redressing of physical and mental health at every level of analysis.”

Connections Between Lack of Sleep and Weight Gain

Consider the fact that inadequate sleep has been demonstrated to:

  • Correlate with obesity: One study found that individuals who regularly slept fewer than six hours per night were more inclined to have excess body weight
  • Elevate the risk of Type 2 diabetes: Studies have also shown that proper sleep can improve blood sugar control and reduce other effects of the disease
  • Naturally increase the body’s sense of hunger: Proper sleep better regulates the production of ghrelin and leptin, the hormones that regulate the body’s feelings of hunger and satiety, respectively
  • Raise calorie consumption: Up to an extra 300-400 calories per day
  • Decrease strength and stamina: This impacts your potential to apply load efficiently and build muscle

Learn More: What are the Consequences of Sleep Deprivation?

Other Science Behind Sleep and Weight Loss

A study performed at the University of Chicago revealed that cutting back on sleep substantially undermines efforts to lose fat through dieting. In fact, results showed it reduced fat loss by as much as 55%.

During weeks with adequate sleep, the subjects lost 3.1 pounds of fat and 3.3 pounds of fat-free body mass–nearly half of the weight they lost through dieting was fat. However, when they cut back on their sleep, only 20% of their weight loss came from fat. The participants also felt hungrier when they got less sleep. As outlined previously, restricted sleep will yield higher levels of ghrelin, a hormone that triggers hunger and reduces energy expenditure.

In another study, it was found that short sleep and sleep loss impaired metabolism and insulin resistance. The rate of clearing sugar out of the bloodstream was 40% slower than when participants were well-slept.

Additionally, Short sleepers secreted 50% more insulin than normal sleepers to reach similar glucose results, placing them at a risk for developing insulin resistance in the long-term. Insulin resistance impairs the body’s ability to burn fat for energy and is a primary contributor to weight gain.

Also worth noting, short 6-night sleep deprivation periods generated metabolic profiles in otherwise healthy young men that mimicked those of people with Type 2 diabetes.

How Does Sleep Affect Weight Loss?

These discoveries help us appreciate the fact that sleep plays a critical role in stabilizing all major functions of the body. It helps regulate the hormonal system, manages the autonomic nervous system (your body’s fight or flight response), and improves a variety of cognitive activities.

We are just now beginning to understand the massive influence sleep has in driving the behaviors (and the regulation of critical systems) in the body that ultimately support the metabolic health change necessary to achieve and maintain your desired goals related to body composition.

The message for people trying to lose weight is clear–sleep makes a big difference in the results of any dietary intervention you attempt to employ. Optimal metabolic health (relative to your potential) is not possible without sufficient, quality sleep.

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Kristen Holmes

Kristen is the VP Performance Science at WHOOP. Before joining WHOOP in 2016, she was the Head Field Hockey Coach at Princeton University. One of the most successful coaches in Ivy League history, Kristen won 12 league titles in 13 seasons, and one National Championship. She was also a 3x All American and a 2x Big 10 Athlete of the year at the University of Iowa, competing in both Field Hockey and Basketball Previously a 7-year member of the U.S. National Field Hockey Team, Kristen blends her background in athletics, coaching, performance technology, psychology and sports performance to drive research and partnership initiatives to strengthen WHOOP as a leader in Human Performance.

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