Ghrelin is a fast-acting hormone, produced in cells of the stomach, which spurs appetite and drives us to eat. Ghrelin may particularly increase appetite for high-calorie foods. There’s evidence that ghrelin may also direct fat towards the midsection of the body, where it is most dangerous to health. When the body is deprived of sleep, production of ghrelin increases. Research shows that even a single night of sleep deprivation can elevate ghrelin levels -- and appetite.
Leptin is a hormone that suppresses appetite by communicating to receptors in the brain that the body has the energy it needs to function, and doesn’t need to take on more. Leptin is produced in white fat cells throughout the body. The amount of fat in the body, then, influences the amount of leptin produced. When leptin levels are lower than normal, we’re less likely to feel full after eating. Food also appears more enticing to people with low leptin levels, according to research. Low sleep suppresses leptin production, making us more likely to feel ongoing pangs of hunger. Even short-term sleep deprivation has been shown to reduce leptin levels.
With these hormonal imbalances at work, it’s little surprise that sleep-deprived people are more likely to gain weight, and to have difficulty maintaining a healthy weight. More than a third of adults in the US are obese, as are 17 percent of children, according to the Centers for Disease Control. Obesity, with its increased risks for many serious health problems -- including diabetes, heart disease, stroke, and some types of cancer -- is arguably our nation’s leading public health problem. A recent study by the CDC projects that half of all adults in the US will be obese by the year 2030. Our collective weight problem endangers millions of lives and costs billions of dollars.