Association Between Vegan, Vegetarian, and Omnivorous Diets and Overweight and Obesity

Association Between Vegan, Vegetarian, and Omnivorous Diets and Overweight and Obesity by Daniel Sullivan MPH, University of Connecticut MS, Rutgers University Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Public Health, Epidemiology Walden University February, 2012 Abstract Overweight and obesity and associated health risks have become epidemic in several regions around the world. Numerous studies have addressed the dietary habits of vegetarians and vegans in terms of disease prevention and nutritional deficiencies but the relationship between overweight and obesity and the demographic, psychosocial, lifestyle, and dietary intake of omnivores, vegetarians, and vegans has received lessOverweight and obesity and associated health risks have become epidemic in several regions around the world. Numerous studies have addressed the dietary habits of vegetarians and vegans in terms of disease prevention and nutritional deficiencies but the relationship between overweight and obesity and the demographic, psychosocial, lifestyle, and dietary intake of omnivores, vegetarians, and vegans has received less attention. Guided by the social-ecological model, this study included a cross-sectional, quantitative, anonymous web-based survey to obtain dietary information on omnivores, vegetarians, and vegans. Vegans demonstrated a significantly lower mean and median body mass index (p=0.00) than omnivores, semi-vegetarians, and vegetarians. Multiple logistic regression analysis demonstrated no significant difference in the odds of overweight (OR=0.41; p=1.14) and obesity (OR=0.47; p=0.28) in vegans compared to omnivores. Alcohol was significantly protective against obesity for both 1-2 (OR=0.33; p=0.03) and 3-30 (OR=0.20; p=0.01) days drinking per month while binge drinking significantly increased the odds of obesity (OR=4.44; p=0.01). Multiple logistic regression analysis stratified for levels of exercise revealed an interaction between diet and exercise. A vegan diet was significantly protective against obesity for low-level exercise in terms of frequency (OR=0.31; p=0.02) and total minutes per week (OR=0.23; p=0.02) compared to omnivores. Coupled with prior studies these results may contribute to positive social change by facilitating a broad-based paradigm shift in the view of diet and exercise as well as providing evidence that can be implementated in broad-based obesity control programs to reduce the morbidity and mortality associated with obesity. Association Between Vegan, Vegetarian, and Omnivorous Diets and Overweight and Obesity by Daniel Sullivan MPH, University of Connecticut MS, Rutgers University Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Public Health, Epidemiology Walden University February, 2012 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent on the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. All rights reserved. This edition of the work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 1346 UMI 3486868 Copyright 2011 by ProQuest LLC. UMI Number: 3486868 Acknowledgments My sincerest thanks to Jessica M. Sullivan for inspiration and to Rebecca J. Sullivan and Lyndsay A. Sullivan for their assistance in navigating social media. Thanks to Paula Clogher who provided direction and clarification on statistical issues. The thoughtful comments and issues raised by committee member Dr. Frederick Schulz were invaluable during the proposal and dissertation process. Thanks to Dr. Ji Shen for reviewing the proposal and dissertation. A special note of thanks to Dr. James Rohrer, without whom nothing past the original concept would have been possible. He allowed me to work independently in my atypical style which included wandering off target now and then. He possessed the wisdom to know when to let me stray and when to reel me back in. He constantly amazed me with the speed and alacrity of his responses with just enough direction to often resolve issues on my own. He also knew the right time to provide a much needed push during the slow periods. Dr. Rohrer helped make this process an enjoyable ride while never loosing site of the destination.