How Sleep Loss Affects Weight Gain
In 2010, public health scientists estimated that 1.5 billion of the world’s population was overweight and 500 million were clinically obese. Current trends for Americans were particularly alarming: The estimate is that 75% of the U.S. population will be overweight or obese by 2020. The basic problem has been growing for a long time: an energy imbalance due to the availability of caloric-rich food and decreasing energy expenditures as a result of sedentary lifestyles in an industrialized society.
But that’s not the entire picture. Scientists have learned about another important factor that was not evident until recently: insufficient sleep. They found compelling evidence that sleep loss leads to metabolic disturbances which increase the positive energy imbalance and result in weight gain. This is actually a vicious circle because excess weight is a cause of sleep apnea, which in turn leads to more sleep disruptions.
Recent studies of healthy volunteers with normal weights show that even short periods of sleep deprivation lead to metabolic disturbances of sugars as well as increased appetites.
Other studies show that abnormal sleep-wake cycles (like those related to shift workers) disrupt biological rhythms for sleeping, hunger and eating. When people don’t eat at their normal meal times (for example, eating at night), they gain weight.
When considering how to approach unwanted weight gain, we must now account for three major factors: nutrition, physical activity and sleep.