2005 Annual Meeting Tuesday Highlights: Low-Tech Weight Management Strategies

- Getting Enough Sleep, Listening to Music and Optimizing Exercise Duration May Aid Weight Control -

Vancouver, British Columbia - October 18, 2005 While there is no magic bullet for weight loss, a number of simple, everyday activities hold promise in helping people reach or maintain a healthy weight. Several new studies being presented today at the 2005 Annual Scientific Meeting of NAASO, The Obesity Society, highlight low-tech strategies that may aid successful long-term weight management.

Short Sleep Duration is Associated with Reduced Leptin Levels and Increased Body Weight: Results from the Quebec Family Study (82-OR; 8:45 a.m. PT) The first study suggests that weight control may be the latest reason why a good night's sleep is essential to health. Researchers from Laval University concluded that sleep may influence levels of leptin, a hormone important in energy balance. Accordingly, there may be an "ideal sleep zone" that facilitates body weight regulation.

"This is a new and very exciting area of research which raises the possibility that lack of sleep may be an unrecognized and potentially modifiable risk factor for obesity," explained Jean-Philippe Chaput, a doctoral candidate in the division of kinesiology at Laval University in Quebec, Canada, who conducted the study. "Getting the optimal amount of sleep, along with modifications to diet and exercise may become an integral prevention and treatment strategy for weight management."

There has been increasing interest among researchers in the possible connection between the worldwide rise in obesity and declining length of sleep. For example, Americans sleep one to two hours less per night than they did 40 years ago. At the same time, rates of obesity have increased dramatically over the past 20 years. Other studies have linked high BMI with shorter sleep as well as shorter sleep with low levels of leptin. While it has been theorized that low levels of leptin may be one reason heavier people sleep less, the team from Laval sought to determine if short sleep is associated with higher body fat measures and lower levels of leptin.

In the study, 740 normal weight, adult men and women participating in the decades-long Quebec Family Study reported their average nightly amount of sleep via a questionnaire. The researchers measured body composition and body fat using hydrostatic weighing and indices including BMI, skinfold thickness and waist circumference. Blood samples were taken to determine lipid profiles and leptin levels.

The researchers found a significant negative correlation between sleep duration and measures of body fat, meaning the short sleepers were heavier. Specifically, they observed lower body weight and body fat values in the normal sleepers (7-8 hours) as compared to the short sleepers (5-6 hours). However, the associations were no longer significant after adjusting for leptin, indicating variations in leptin levels were responsible for the association. Further analysis showed that the majority of short sleepers (88 percent) had lower levels of leptin than the normal sleepers.

Leptin is a hormone that decreases energy intake and increases energy expenditure - the hallmarks of weight control. In normal weight individuals, low levels of leptin favor a positive energy balance, leading to weight gain. It has been observed that overweight individuals have high levels of leptin, but are resistant to its effects.

Effect of Varying Doses of Exercise on 24-Month Weight Loss in Overweight Adults

(96-OR; 10:45 a.m. PT) According to results from the longest study to date examining duration of exercise on weight loss, getting approximately 300 minutes of exercise a week appears to facilitate the greatest weight loss among obese individuals. Government guidelines currently recommend that all people engage in approximately 150 minutes of physical activity each week.

"Clearly, overweight individuals have different exercise needs than the general public when it comes to increasing their energy expenditure. To maximize weight loss and minimize weight regain, it appears that overweight individuals should supplement dietary changes with approximately 300 minutes of exercise each week, which is twice the amount recommended for health in the general public," noted lead investigator John Jakicic, Ph.D., chair of the department of health and physical activity at the University of Pittsburgh.

Participants in the study were 191 overweight adult women with a mean BMI of 32.7. In addition to a low calorie/low fat diet, the women were assigned to one of four exercise regimens: moderate or high dose (based on the number of kcal to burn each week) and moderate or high intensity. At the end of two years, all of the women lost weight, with those in the high duration/vigorous intensity group losing the most - an average of 7.2 percent of their initial body weight.

However, the women did not necessarily exercise at their prescribed dose and intensity, so the researchers also assessed weight loss at 12 and 24 months based on the amount of time the women self-reported exercising. The amount of exercise fell into five categories:

• <150 minutes/week at 12 months and at 24 months
• >150 minutes/week at 12 months and at 24 months
• >200 minutes/week at 12 months and at 24 months
• <150 minutes/week at 12 months and >150 at 24 months
• >150 minutes/week at 12 months and <150 minutes at 24 months

The women who exercised the most -- those in the >200 minutes at 12 and 24 months -- did so for an average of 309 minutes/week at month 12 and 270 minutes/week at month 24. Data analysis showed that these women experienced a 13 percent weight loss over 24 months, significantly greater than all of the other groups except those exercising <150 at month 12 and >150 at month 24. The women in this study were followed longer than any other similar study, and the results are consistent with findings seen since 1999. Dr. Jakicic suggests that educating practitioners and overweight individuals about sustaining 270 to 300 minutes of weekly physical activity will help more people achieve successful weight loss and maintenance.

Effect of Music on Exercise Adherence and Treatment Outcomes in a Study of Overweight to Moderately Obese Women (783-P; 9:45 a.m. PT) Could an IPod aid in weight loss? Results of a new pilot study suggest that listening to music while exercising helps overweight people stick with exercise and get better results from their weight loss program. According to Christopher A. Capuano, Ph.D., director of the school of psychology at Fairleigh Dickinson University in Teaneck, NJ, one of the biggest barriers to long-term weight control is lack of adherence to an exercise regimen. However, few controlled studies have examined the logical assumption that better exercise and treatment adherence will lead to better weight loss outcomes.

"Exercising can be difficult for someone who is obese. Walking to music seemed to really motivate the women in our study to get out there and stick with the commitment they made," noted Dr. Capuano.

The researchers evaluated the effects of music on exercise adherence in 41 women who were overweight to moderately obese (BMIs ranged from 26.1 to 41.7) as part of a 24-week weight loss program that included dieting, aerobic exercise and participation in weekly group meetings. The women were expected to walk alone for a minimum of two days per week, plus participate in one group walk. The group walks got progressively more difficult; in order to keep up, they needed to walk longer distances in a shorter amount of time.

Half of the women were randomized to get a portable CD player so they could play music of their choice when they walked. The other half did not walk to music. At the end of the study both groups of women lost weight, but those who walked to music lost significantly more weight and body fat. Additionally, the music group adhered better to the walking component of the program as well as the overall program, and fewer of them dropped out of the study compared to the group without music.

NAASO, The Obesity Society, is a leading scientific society dedicated to the study of obesity. NAASO is committed to encouraging research on the causes, treatment and prevention of obesity as well as to keeping the scientific community and public informed of new advances in the field. For more information about NAASO and obesity, visit www.naaso.org or call (301) 563-6526.