Weight management using the internet a randomized controlled trial.

BACKGROUND: Most weight-loss research targets obese individuals who desire large weight reductions. However, evaluation of weight-gain prevention in overweight individuals is also critical as most Americans become obese as a result of a gradual gain of 1-2 pounds per year over many years. METHOD: This study evaluated the efficacy of an Internet-based program for weight-loss and weight-gain prevention with a two-group, prospective, randomized controlled trial. A military medical research center with a population of 17,000 active-duty military personnel supplied 446 overweight individuals (222 men; 224 women) with a mean age of 34 years and a mean BMI of 29. Recruitment and study participation occurred 2003-2005 and data were analyzed in 2006. Participants were randomly assigned to receive the 6-month behavioral Internet treatment (BIT, n=227) or usual care (n=224). Change in body weight, BMI, percent body fat, and waist circumference; presented as group by time interactions, were measured. RESULTS: After 6 months, completers who received BIT lost 1.3 kg while those assigned to usual care gained 0.6 kg (F((df=366))=24.17; I<0.001). Results were similar for the intention-to-treat model. BIT participants also had significant changes in BMI (-0.5 vs +0.2 kg/m(2); F((df=366))=24.58); percent body fat (-0.4 vs +0.6%; F((df=366))=10.45); and waist circumference (-2.1 vs -0.4 cm; F((df=366))=17.09); p<0.001 for all. CONCLUSIONS: Internet-based weight-management interventions result in small amounts of weight loss, prevent weight gain, and have potential for widespread dissemination as a population health approach. TRIAL REGISTRATION: NCT00417599.

Meteorological conditions are associated with physical activities performed in open-air settings.

Meteorological conditions (MC) are believed to modify physical activity. However, studies in this area are limited and none have looked at the associations between MC and physical activity in open-air settings. Therefore, we examined the relationships between MC and physical activities performed on sidewalks/streets and outdoor oval tracks. Observation techniques were used to count individuals walking to school, exercising on oval tracks and walking/jogging/biking on sidewalks/streets. Meteorological conditions were obtained from an Automated Surface Observing System located at a nearby airport for the same time periods physical activities were observed. On weekdays, fewer children were seen walking to school and more bicyclists were observed on sidewalks/streets as wind speed increased (p < 0.05). Ambient and apparent temperatures were positively (p < 0.05) and humidity and barometric pressure negatively (p < 0.005) related to the number of individuals walking on the track. Meteorological conditions were not significantly associated with physical activities observed on weekends. Multiple linear regression analyses showed that apparent temperature (+), barometric pressure (-) and dew point (-) accounted for 58.0% of the variance in the number of walkers on the track. A significant proportion of the variance (>30%) in the number of joggers and the length of time they jogged was accounted for by apparent temperature (+) and dew point (-). We found that meteorological conditions are related to physical activity in open-air settings. The results embellish the context in which environmental-physical activity relationships should be interpreted and provide important information for researchers applying the observation method in open-air settings.