Sleep, regular exercise and good diet are essentials for good health and weight control. Researchers at Columbia University found that people who sleep less than 7 hour per night are, in average, heavier and tend to gain more weight over time.
We explain why better sleep help you to lose and maintain a healthy weight.
Sleep deprived people report having an increased appetite. This is caused by two hormones responsible for signalling hunger in our brains. Ghrelin is released to signal hunger in the brain. Leptin is released from fat cells, it suppresses hunger and signal fullness. Not sleeping deregulate the release of those hormones, increasing your appetite.
Researchers at University of Pennsylvania found that sleep restricted people gained more weight, in part because of an additional consumption of 550 calories between 11pm to 4am.
As people look for easier and faster foods late at night, those snacking tend to be more calorie dense and heavily processed than other meals during the day. This phenomena might be related with the hormonal unbalance explained above, but may be also due simply by an increase in time spend awake and availability to eat.
Our brain is affected by lack of sleep, making it harder for us to make good choices. Sleep deprivation slows the activity of our frontal lobe of the brain, which is responsible for decision making. At the same time, the reward centers are more stimulated by food when you are sleep deprived.
Lack of sleep causes daytime fatigue, which makes easy and quick meals more appetizing. Also, it decreases the motivation for exercise and the intensity of physical activity.
Sleep also has a positive impact in athletic performance. College basketball players who spend 10 hours in bed each night had their reaction time improved, became faster and enhanced their accuracy levels.
Insulin is the hormone responsible for moving sugar into our cells, to be transformed in energy. If our muscle cells lose sensitivity to this hormone, more sugar remains in the bloodstream and the body compensate producing more insulin. The excess insulin tends to make us hungrier and increase the transformation of sugar into fat.
The body of people who are sleep deprived tend to have a higher insulin resistance. In one study, men who were allowed to sleep four hour for six nights had their capacity to lower blood sugar levels by 40%.
Besides weight gain, this mechanism is the precursor of type 2 diabetes. It’s a disease associated to reduce lifespan in 10 years due the increased risk of cardiovascular disease and kidney failure. It also highly increases the risk of life changing conditions, such as lower limb amputation, blindness and sexual dysfunction.
The number of calories your body burns while rested is affected by age, weight, sex and muscle mass.
In one study, men were kept awake for 24 hours and had their metabolism 5% lower than their average after a good night’s sleep. Their metabolic rate after eating was decreased in 20%.
Not sleeping lead to muscle loss, which decreases the metabolism even further. Muscle burns more calories at rest than fat does. For effects of comparison, 10kg loss of muscle mass may lower your resting metabolism in approximately 100 calories per day.