Sleep and Weight Loss
The amount of sleep you get and the quality of it directly influences your body composition. Getting too little or even too much sleep can negatively affect your body fat levels and even your health. When it comes to weight loss, most people only focus on their diet and exercise program. Instead, they should be focused on their diet, exercise, and rest/recovery. Leaving out any one of those three pillars will negatively affect your fitness.
What are some of the causes of weight gain when you don’t get enough sleep?
- Changes in Glucose Metabolism – Sleep deprivation results in increased blood glucose and insulin levels  . It also causes insulin resistance . When insulin levels remain elevated, growth hormone levels are inhibited. Growth hormone is anabolic to muscle tissue and catabolic to fat tissue. It’s a very important hormone when it comes to weight loss.
- Increased Appetite – Short sleep is associated with reduced leptin levels, elevated ghrelin levels, and increased hunger and appetite  . Leptin and ghrelin are “hunger” hormones. When leptin levels are low, it’s a signal to your body to eat more food.
- Physical Activity – Sleep restriction significantly decreases physical activity during the day . Less physical activity means less energy expenditure. I don’t think it’s much of a stretch to think that not getting enough sleep will result in feelings of being tired, lazy, or lethargic during the day. We’ve all been there before.
There is a strong correlation between short sleep duration and future weight  . People that sleep less than 7 hours a night have a much higher likelihood of weight gain in the future. Based on the following chart comparing the hours of sleep per night to body mass index, it would seem the sweet spot for sleep is between 7-9 hours per night. Anything less or more results in a higher body mass over time.
Sleep and Your Health
Individuals that sleep either 6 or fewer hours a night or more than 9 hours showed an increased risk of coronary heart disease . Less physical activity and the onset of insulin resistance resulting from less sleep are leading causes for poor cardiovascular health.
Diabetes and sleep are also correlated. Men and women who slept less than 5 hours or more than 9 hours had an increased risk for developing diabetes  . Since sleep duration and glucose/insulin levels are negatively correlated (when sleep is low, glucose and insulin levelsare high), it’s quite easy to make the link between type II diabetes and sleep loss.
Do You Lose Weight When You Sleep?
Perhaps you’ve heard the idea promoted that you can lose weight in your sleep. All gimmicky infomercials aside, you absolutely do lose weight when you sleep. In fact, when you sleep, your body has a very favorable metabolic environment that is conducive to fat loss. When you sleep you have:
- High Growth Hormone Levels – The majority of your growth hormone secretion happens at night. Growth hormone builds muscle mass, increases protein synthesis, and promotes fat loss. Many people even consider this hormone the fountain of youth.
- Lower Blood Glucose and Insulin Levels – Assuming you are eating correctly and not bombarding your body with high-glycemic carbohydrates right before bed, your body will have lower insulin levels. These lower insulin levels stimulate the release of other hormones that mobilize fatty acids.
Does Sleep Help You Lose Weight?
I think the scientific literature is overwhelmingly clear that sleep does help you lose weight. More specifically, getting in between 7-9 hours of sleep per night seems to be optimal for good body composition and general health. The good news is that improved fitness levels improve the quality of your sleep. So if you’re living the fitness lifestyle, you’re on the right path towards optimized sleep patterns. Not only does sleep affect your nutrition and exercise, but nutrition and exercise affect your sleep. Sleep and rest are a very important and often overlooked part of fitness – be sure you’re making them a priority.MUST READ: The Definitive Guide for How to Lose Weight
FREE EBOOK: The 10 Forgotten Rules of Weight Loss