Trial Information

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.