Lack of sleep may promote obesity

New research shows a connection between short-term sleep deprivation and increased food intake, indicating that lack of sleep may be a factor that promotes obesity.

It is known that short-term sleep deprivation increases plasma concentrations of ghrelin (a hormone related to increased appetite) and decreases those of leptin (a hormone related to satiety.)

In a randomized crossover study, researchers studied twelve normally healthy non-obese men to observe the effect of sleep deprivation on energy intake and physical activity. During the first night of each 48-hour session, subjects had either 8 hours (from midnight to 8:00 a.m.) or 4 hours (from 02:00 a.m. to 06:00 a.m.) of sleep. All foods consumed thereafter (jam on buttered toast for breakfast, buffet for lunch, and a free menu for dinner) were eaten ad libitum (with no restrictions.) Physical activity was also recorded. Sensations of hunger, perceived pleasantness of the foods, desire to eat some foods, and sleepiness were also evaluated.

In comparison with the 8-hour sleep session, subjects consumed 559 (22%) more calories on the day after sleep restriction, and hunger was higher before breakfast and dinner. Researchers observed no change in the perceived pleasantness of the foods or in the desire to eat the foods. Physical activity was slightly higher after sleep restriction than after 8 hours of sleep, even though the sensation of sleepiness was more apparent.

In this group of healthy men, one night of reduced sleep led to an increase in food intake and, to a lesser extent, physical activity-related energy expenditure. Although further research is needed to confirm the results of this small study, these results suggest that sleep restriction could be a factor that promotes obesity.

Source: Acute partial sleep deprivation increases food intake in healthy men. Laurent Brondel et al Am J Clin Nutr 91: 1550-1559, 2010.

Source: USANA Health Sciences

USANA-Supported Clinical Study Results Published in the Journal Obesity and Weight Management

USANA Health Sciences, Inc. (NASDAQ: USNA) announced today that results of a large, third-party clinical study involving USANA products, conducted at the University of Colorado Denver (UCD), have been published in the August 2009 edition of the journal Obesity and Weight Management.

The recently completed study confirms that lifestyle change can significantly improve outcomes in subjects with metabolic syndrome. Metabolic syndrome is a pre-diabetic state that involves multiple symptoms including central obesity, insulin resistance, elevated blood lipids, elevated blood glucose, and high blood pressure. The 12-week-long study was conducted with 60 people diagnosed with metabolic syndrome. Subjects followed an Internet-based lifestyle modification program that included USANA's nutritional supplements, moderate exercise and a low-glycemic diet including USANA's nutritional shakes and bars.

Over the 12-week program, subjects in the study lost an average of 12 pounds and experienced significant improvements in measures of glycemic control, cardiovascular risk factors, inflammation and antioxidant status. Importantly, by the end of the trial, one-third of the subjects no longer met the criteria for metabolic syndrome.

Holly Wyatt, a physician and faculty member of the University of Colorado's Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, oversaw the study.

"This is a very promising program that produced some very positive changes in the cardiovascular risk factors associated with the metabolic syndrome," Dr. Wyatt said. "The shifts in dietary habits to calorically restricted low-glycemic meals and the modest increases in physical activity were not only effective but also are realistic behavioral changes many people can make."

“We are thrilled with the results of this clinical study and are excited to see it published in Obesity and Weight Management,” said Tim Wood, USANA’s Executive Vice President of Research and Development. “It is gratifying to have independent confirmation that our products and approaches to healthy lifestyle management work.”

Source: Successful Internet-Based Lifestyle Change Program on Body Weight and Markers of Metabolic Health, Wyatt et al, Obesity and Weight Management, August 2009

Source: Usana Health Sciences