from Dr Weil's weekly newsletter: Everyone knows the basic contributors to obesity: eating too much and exercising too little. But why is cutting calories so difficult for so many people? Recent research suggests that lack of sleep may be a prime culprit. Researchers from Universite’ Laval’s Faculty of Medicine in Quebec City, Canada, studied the habits of 422 grade-school students. They found that the risk of becoming overweight is 3.5 times higher for children who get less than 10 hours of sleep nightly than for those who get 12 or more hours. No other factor analyzed in the study, including parental obesity, family income or even physical activity, had as much impact on obesity as time spent sleeping. Other studies have shown a similar link in adults between lack of sleep and obesity. The reason proposed is that sleep deprivation boosts ghrelin, a hormone that stimulates the appetite, and reduces leptin, which suppresses appetite. This does not surprise me. Adequate sleep is a fundamental building block of good health, and it makes sense that skimping on sleep could throw hormonal regulation of appetite out of whack. It also makes sense when one considers that obesity and sleep deprivation seem to be rising in tandem in modern society. Getting more sleep is obviously not the whole answer to conquering obesity, but for those who struggle with this issue, it should be an important part of any plan to take control of the problem.