Vegetarians have a lower risk of obesity than non-vegetarians in high and low obesity environments

Background: Obesity has become an epidemic in the U.S. and other countries with detrimental effects to the quality of life and health perspectives. Lifestyle factors such as dietary patterns may contribute in the prevention of obesity. Objective: The purpose of the study was to investigate associations between dietary patterns based on the inclusion or absence of meat and obesity in high and low obesity environments. Methods: Cross-sectional study of 55676 U.S. subjects (age range 30 to 110 years) from the Adventist Health Study-2 with a complete set of data. Dietary pattern was classified as vegetarian and non-vegetarian based on meat intake derived from a validated food frequency questionnaire. County-level estimates of obesity provided by the CDC were stratified in quintile levels and cohort based individual level BMI values were calculated. Logistic regression analysis was employed to assess the association between dietary pattern and obesity stratified by quintiles of county-level obesity prevalence. Adjustments were made for cohort based information on race, sex, age, physical activity, caloric intake and sedentary behavior. Results: After multiple adjustments the odds ratios of being obese were substantially lower for vegetarians than non-vegetarians in all quintiles of county level obesity with odds ratios (OR) between 0.460 and 0.522. The odds ratios for vegetarians were lowest in counties with the two highest obesity quintiles (4th quintile OR=0.460, CI=0.406-0.521 and 5th quintile OR=0.469, CI=0.400-0.549). Conclusions: A vegetarian diet is associated with a lower risk of being obese in high and low obesity environments and may show the greatest benefit in higher obesity environments.