The study was published in the Dec. 7 issue of the Annals of Internal Medicine. The editorialists suggest that getting enough sleep may help reduce weight gain.

"Total sleep deprivation in rodents and in humans has been associated with hyperphagia," write Karine Spiegel, PhD, from the University of Chicago in Illinois, and colleagues. "Over the past 40 years, self-reported sleep duration in the United States has decreased by almost two hours."

In this two-period, two-condition crossover clinical study, 12 healthy men were randomized to two days of sleep restriction (four hours per night) and two days of sleep extension under controlled conditions of energy intake and physical activity. Mean age was 22 ± 2 years, and mean body mass index (BMI) was 23.6 ± 2.0 kg/m2. Outcomes were daytime profiles of plasma leptin and ghrelin levels and subjective ratings of hunger and appetite.

During sleep restriction, there was an 18% decrease in the anorexigenic hormone leptin (P = .04), 28% increase in the orexigenic factor ghrelin (P < 0.40), 24% increase in hunger (P < .01), and 23% increase in appetite (P = .01), especially for energy-dense foods with high carbohydrate content (increase, 33% to 45%; P = .02).

"Short sleep duration in young, healthy men is associated with decreased leptin levels, increased ghrelin levels, and increased hunger and appetite," the authors write. "Additional studies should examine the possible role of chronic sleep curtailment as a previously unrecognized risk factor for obesity."

In an accompanying editorial, Jeffrey S. Flier, MD, and Joel K. Elmquist, DVM, PhD, from Beth Israel Deaconess Medical Center in Boston, Massachusetts, wonder if controlled studies should be designed to measure the effect of sleep-promoting interventions on appetite and body weight. However, they note that this study does not prove a cause-effect relationship between the hormone levels and hunger and dietary intake. Other factors, such as cortisol or orexin, may affect sleep and body weight regulation.