Reducing the prevalence of obesity in the population is one of the Healthy People 2010 goals. Increased vigilance is required in all age groups in preventing and reversing overweight and obesity. On an individual level, behavioral factors that influence body weight include eating choices leading to excess calorie intake and physical activity patterns leading to diminished calorie expenditure. An imbalance between the two over time leads to increased weight. On a population basis, the prevalence of overweight is associated with a myriad of influences, including social, behavioral, cultural, and environmental factors as well as genetic and physiological factors. For a majority of overweight individuals, restoring a balance between energy intake and expenditure is difficult, and therefore there is an increasing emphasis on preventing obesity on a population level. The long-term goal of this research is to prevent further increase in rates of obesity in the population. In the adult population of working age, a majority of the day is spent in the worksite, suggesting that interventions at the worksite level may offer the opportunity for success in this age group. It is anticipated that this project will yield important contributions to the understanding of obesity prevention.

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.

The study is enrolling employees only at participating worksites.

INCLUSION CRITERIA FOR WORK SITES:

• Meets specific standard industrial codes
• At least 20% of employees are sedentary
• Willing to provide a list of employees
• Able to achieve at least a 70% response rate to the baseline survey