Reducing Obesity at the Workplace: a Randomized Trial

BACKGROUND:

More than half of American adults are overweight or obese, and this proportion is increasing. The health risks associated with obesity include diabetes, cardiovascular disease, arthritis, and some cancers. It is well established that on an individual level, weight gain is caused by taking in more calories than are expended. On a population basis, the prevalence of overweight and obesity is associated with a myriad of influences, including genetic and physiological factors as well as social, behavioral, cultural, and environmental factors. Behavioral factors that contribute to weight gain include eating choices that lead to increased energy intake and physical activity choices that lead to decreased energy expenditure. For a majority of overweight individuals, restoring the balance between energy intake and expenditure is difficult.

DESIGN NARRATIVE:

This study will develop and test a comprehensive intervention involving simple messages that will integrate changes in dietary intake with changes in energy expenditure, while simultaneously modifying structural and environmental factors to promote social support and opportunities for behavioral change. The study will recruit and randomize 48 worksites to a 2-year intervention in which the following will be carried out: build a physical activity intervention combining increased daily physical activity and regular, structured exercise; build a dietary intervention that will promote lower calorie intake; and increase worksite access to both healthy foods and physical activity. The primary aim is to evaluate the effectiveness of the intervention in reducing or maintaining body mass index in a randomized controlled trial of worksites. The study will compare changes in body mass index in intervention versus control worksites using two cross-sectional surveys at baseline and follow-up. Additional assessments using biomarkers and fitness measures will be performed in a subset of employees. The research team has considerable experience with interventions at the worksite level and substantial expertise in obesity prevention.