It is no secret that our society struggles with weight loss resistance. Researchers at John Hopkins University estimate that by the year 2015 over 75% of Americans will be overweight with a staggering 41% being obese. Many people claim the country’s propensity to overeat and indulge on junk food on a lack of will power; however, science is now showing it may be related to our hormones. New research is showing that healthy sleep cycles have been shown to balance the hormones responsible for food cravings and overeating.
Ghrelin is a hormone that is produced by the stomach during times of famine. This hormone, isolated and named in 1999, stimulates hunger and digestive function. When we fast for several hours, our body begins to increase ghrelin production which interacts with the neurons in the metabolic control center of our hypothalamus, and we begin to feel hungry.
Leptin is a hormone secreted by our fat cells that interacts with the hypothalamus and creates feelings of satiety that shut down our hunger center. When we fast, ghrelin levels rise. When we eat, insulin and leptin levels rise and ghrelin levels drop. Higher levels of ghrelin have been associated with cravings for sugar-rich, calorie-dense junk food.
Many people go on calorie restricted diets in order to lose weight. However, calorie restriction leads to dramatic increases in ghrelin secretion. This results in uncontrollable hunger and eventual over-eating. This is the hormone responsible for the classic starvation-binge cycle that ruins so many weight loss pursuits. This is also why deprivation based weight loss programs have a very poor long-term success rate.
Sleep may be the Most Important Lifestyle Factor for Weight Loss. Researchers at Stanford University found that people who sleep 5 hours or less per night had a 15% greater amount of ghrelin and 15% less leptin than those who slept 8 hours a night. Another study showed that sleep deprived individuals had a significantly greater craving for carbohydrate rich junk food.
Leptin and ghrelin work as a check and balance system to control feelings of fullness & hunger. Poor sleep cycles drive leptin down and increase ghrelin. This drives the individual to have less satisfaction after eating and instead to crave more food leading to weight gain. Overtime the individual will become leptin resistant, which virtually shuts down the body’s ability to effectively burn fat. The sleep hormone melatonin has been shown to help heal leptin receptors and restore normal leptin sensitivity, which is critical for healthy weight loss and fat burning mechanisms in the body. Sleep deprived individuals do not secrete enough melatonin to restore normal leptin function.
Sleeping has also been shown to enhance human growth hormone (HGH) secretion, which is our body’s natural anti-aging hormone. HGH secretion switches our metabolism to burn fat, build muscle, & boost immunity. Elevated insulin levels are antagonistic to HGH. Therefore, eating food (particularly carbohydrate rich food) before we sleep at night is detrimental to our efforts to effectively burn fat.
Keys to a Good Night Sleep:
1) Do not eat within 3 hours of sleep
2) Eat low carbohydrate meals throughout the day and particularly at night.
3) Keep your bedroom cool (around 70F/21C)
4) Light inhibits melatonin secretion so keep your bedroom as dark as possible.
5) If you must eat before bed – have good fat/protein such as a shake with coconut milk, almond butter, cinnamon, & stevia.
6) Regular movement throughout the day helps burn off metabolic waste in muscles and cells allowing the body to relax more effectively.
7) Avoid caffeine and stimulants after 3pm