Sleep Deprivation Increases Cravings for Junk Food
Insufficient sleep has long been linked to numerous health problems including excessive weight gain. Research has shown that individuals who skimp on sleep weigh more than those who get enough. For example, The Nurse’s Health Study, which followed more than 60,000 women for up to 16 years, found that women who slept fewer than five hours per night were at greater risk for gaining significant weight – up to thirty pounds – than women who averaged seven or more hours of sleep.
There are many possible reasons for the relationship between poor sleep and weight gain. For one, short sleepers may be too tired to engage in physical activities thereby reducing their chance of burning enough calories. In addition, it has been reported that sleep deprivation increases ghrelin, an appetite-stimulating hormone, while lowering levels of leptin, a hormone that induces satiety. By altering these hormones, sleep deprivation spikes feelings of hunger in general and increases cravings specifically for calorie-rich foods such as processed sugars and junk food. Moreover, simply by being awake more hours each day, sleep deprived persons have more opportunities to eat during their extra waking hours, thus increasing their caloric intake.
The amount of leptin in the blood is inversely correlated with endocannabinoid (eCB) which has a role in regulating appetite, feeding and energy homeostasis. Researchers looked at the possible effect of sleep deprivation on the eCB system through a randomized crossover study involving 14 healthy women and men in their twenties. They investigated the role of insufficient sleep in the activation of the eCB system, and its effect on controlling appetite and food intake.
In the first stage, the participants spent four nights sleeping for 8.5 hours and in the next stage, they spent 4 nights with sleep restricted to only 4.5 hours. In both stages, they consumed identical meals provided at 9am, 2pm and 7pm and were only allowed to do sedentary activities.
The 24 hour profiles of circulating concentrations of the endocannabinoid 2-arachidonoylglycerol (2-AG) and its structural analog 2-oleoylglycerol (2-OG) were evaluated. With enough sleep, endocannabinoid 2-AG increases in the morning, further rises after lunchtime and decreases later in the day. On the other hand, during sleep deprivation, subjects showed 33% higher increase in endocannabinoid 2-AG. It was found that the amount of this chemical compound peaks from 2 pm until 9 pm.
Sleep-deprived participants reported increased hunger and appetite particularly in the late afternoon and early evening. After the 4th night of each stage, participants were presented with unhealthy snacks. Sleep curtailed individuals chose snacks with 50% higher calories and nearly twice as much fat content – even though they had just had a full meal within the previous two hours - as those snacks chosen by fully rested subjects. These snacks were also consumed after eating a meal with 90% of their recommended daily calorie intake 2 hours earlier.
The elevation of endocannabinoid 2-AG may boost the cravings for sweet, salty, and high fat foods, as well as stimulate the pleasant feelings of food. This study suggests that the activation of eCBs during periods of sleep debt enhances appetite making it difficult to resist unhealthy foods. The amount of calories in the snacks is also in excess of what they need in their extra waking hours. This proved that sleeping less than the optimal number of hours encourages overeating and contributes to weight gain.
The good news is that increasing the amount of sleep you get by even one hour each night can help you lose up to 14 pounds over the course of a single year.
Follow this link to learn more about natural ways to improve the quality and quantity of your sleep.