When analyzing how sleep affects weight loss – numerous news segments and magazine articles have described how lack of sleep is related to weight gain among adults. In fact, ABC Newsreported that even among children, those who do not get enough sleep are four times higher risk for obesity than those who get optimal sleep. Inadequate sleep among children may also lead to increased appetite, more time to eat, and/or reduced energy expenditure.

How exactly does this happen?

1. Increased appetite: There are two important hormones involved – leptin and ghrelin. Leptin reduces appetite and enhances satiety after a meal. Ghrelin stimulates the appetite and reduces satiety by counteracting cholecystokinin (a.k.a. the full signal). Multiple studies found that people who have chronically poor sleep have low levels of leptin and high levels of ghrelin; and the food people tend to go for are in high carb and high fat.

2. More time to eat: Obviously, for every extra hour people stay up (i.e. adults catching up on work, kids finishing up homework or families watching TV), the opportunity to snack increases.

3. Reduced energy expenditure: Over time, sleep deprivation can lead to fatigue, which makes it difficult to be active. Studies have found the children who sleep less are more likely to watch TV and less likely to participate in sports. Similarly, sleep deprived adults report reduced physical activity level.

So what is adequate sleep? It depends . . .

• Adults: 7-9 hours (The negative effects of sleep deprivation occurs when you get less than 6 hours of sleep)
• Teens: 8.5-9.25 hours
• Children (school age): 10-11 hours