MEAL PATTERNS AND PRACTICAL APPLICATIONS FOR OBESITY MANAGEMENT A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Master of Science Matthew F. Good May, 2008 MEAL PATTERNS AND PRACTICAL APPLICATIONS FOR OBESITY MANAGEMENT Matthew F. Good Thesis Approved: Accepted: Advisor School Director Dr. Deborah Marino Dr. Richard Glotzer Faculty Reader Dean of the College Mrs. Evelyn Taylor Dr. James Lynn Faculty Reader Dean of the Graduate School Dr. David Witt Dr. George Newkome Date ii ACKNOWLEDGEMENTS I would like to extend my appreciation to the Summa Health System of Akron, Ohio, for the gracious permission of use of the data collected through the REACH Trial. I would also like to extend a special thanks to the faculty of The University of Akron, namely Dr. Deborah Marino, Dr. Isabelle Stombaugh (Retired), Mrs. Evelyn, Taylor, and Dr. David Witt. Your dedication to student education and mentoring is surpassed by none. iii TABLE OF CONTENTS Page LIST OF TABLES ...…………………………………………………………………….vii CHAPTER I. INTRODUCTION ...…………………………………………………………………...1 Background ...……………………………………………………………………..1 Purpose and Objectives ...…………………………………………………………4 Research Problem ...………………………………………………………………5 Significance of Study ...…………………………………………………………...5 Assumptions of the Study ...……………………………………………………....6 Limitations of the Study ...………………………………………………………...6 Definitions ...………………………………………………………………………7 II. REVIEW OF THE LITERATURE ...………………………………………………..10 Introduction ...……………………………………………………………………10 Obesity and Fat Cells ...………………………………………………………….10 Obesity and Genetics ...………………………………………………………….11 Obesity and Environment ...……………………………………………………..14 Previous Research ...……………………………………………………………..15 Past Research Discoveries and the Need for Continual Investigation ...………...19 Research Hypotheses ...………………………………………………………….21 iv III. METHODOLOGY ...……………………………………………………………….22 Methodology of the Original Study ...…………………………………………...22 Subjects ...………………………………………………………………..22 Available Data ...………………………………………………………...23 Anthropometric Measurements ...………………………………………..24 Dietary Patterns and Nutrient Intake …………………………………….24 Physical Activity ...………………………………………………………25 Medical History and Psychosocial Questionnaires ...……………………25 Data Collection Procedures ...……………………………………………25 Dietary Recall Database …...…………………………………………….26 Data Processing ...………………………………………………………..26 Methodology of the Current Study ...……………………………………………27 IV. RESULTS/FINDINGS ……………………………………………………………..29 Primary Variables and Subscore Calculations ...………………………………...29 Regression Analysis ……………………………………………………………..33 V. DISCUSSION OF FINDINGS ……………………………………………………...38 Meal Frequency and Energy Intake ……………………………………………..39 Meal Frequency and BMI Change ………………………………………………41 Time of Consumption …………………………………………………………...43 Extenuating Influential Factors ………………………………………………….44 Summary of Findings ……………………………………………………………45 VI. SUMMARY AND IMPLICATIONS ………………………………………………46 Future Research …………………………………………………………………47 v Practical Implications …………………………………………………………....47 REFERENCES ………………………………………………………………………….49 APPENDICES …………………………………………………………………………..55 APPENDIX A. HUMAN SUBJECTS APPROVAL …………………………..56 APPENDIX B. PRIMARY DATA ……………………………………………..57 vi LIST OF TABLES Table Page 1. Variable Legend ……………………………………………………………………..32 2. Summary of Pertinent Variables ………………………………………………….....33 3. Regression Analysis – Association of Meal Frequency and Kcal Consumed per Meal …………………………………………………………………………………34 4. Regression Analysis – Association of Meal Frequency and Weight Change and Body Mass Index Change ...…………………………………………………………34 5. Regression Analysis – Association of Percentage of Kcal Eaten at Night with Total Kcal Consumed per Day …...……………………………………………….....36 6. Regression Analysis – Association of Percentage of Kcal Eaten at Night with Weight Change and Body Mass Change …...…………………………………….....36 vii CHAPTER I INTRODUCTION Background The prevalence of obesity in the United States has increased dramatically over the past decade, and while reducing obesity to less than 15% of the population is a national health objective for 2010, research indicates the opposite is occurring. According to the Center for Disease Control (CDC) Behavior Risk Factor Surveillance System (BRFSS), in 1991, an estimated 12% of the United States population was obese. By the year 2000, the prevalence of obesity had risen to 19.8% of the population, a 61% increase in nine years. By 2000, an estimated 38.8 million people were obese, and increases in the prevalence of obesity were occurring in almost every subgroup of the United States population. According to NHANES 2003-2004, currently 66.2% of U.S. adults, age 20 to 74 years are categorized as overweight (BMI >25). Of the same age group, 32.9% are categorized as obese (BMI >30). With the prevalence of obesity rising to epidemic proportions, the causes of this problem, its health costs, and ways to prevent or treat it need to be addressed (1). Obese individuals have an elevated risk for physical ailments, as reported by Stunkard et al. and the National Institute of Health (2). These risks include hypertension, dyslipidemia, Type II diabetes mellitus, glucose intolerance or insulin resistance, and 1 hyperinsulinemia. Other health risks include coronary heart disease, angina pectoris, congestive heart failure and stroke. Gallstones, cholescystitis and cholelithiasis, and gout are potential health risks. Other possible ailments accompanying obesity are obstructive sleep apnea and respiratory problems, some types of cancers (endometrial, breast, prostate, and colon), poor female reproductive health (menstrual irregularities, infertility, irregular ovulation), bladder control problems (stress incontinence), osteoarthritis, gastroesophageal reflux disease (GERD), and uric acid nephrolithiasis. In addition to these physical hazards, obesity can also be accompanied by psychological disorders such as depression, eating disorders, distorted body image, and low self esteem (2). In addition to the physical ailments associated with obesity, this health problem is a great cause for financial concern in this country. According to Yee et al. (3), the related medical expenses accounted for 9.1% of the total U.S. medical expenditures in 2004, as well as total state expenditures on obesity-related medical expenditures were approximately $75 billion, excluding costs related to absenteeim and loss of productivity. Obesity is a chronic condition that seems to have multiple etiologies. Researchers have found that obesity is a condition caused by a combination of behavioral, environmental, and genetic factors (4). Behavior affects the prevalence of obesity in the most obvious of ways. Energy imbalance occurs when more energy is consumed than is being used. This imbalance can be the result of eating too much, not exercising enough, or a combination of both. Over time, this excess energy can result in weight gain and, eventually, obesity. A more covert, yet equally important obesogenic factor is one’s environment. While the human gene pool has been and is geared towards a hunter-gatherer lifestyle, 2 technologically advanced societies are experiencing increases of obesity in their populations. Historically speaking, an active lifestyle was required for the acquisition of a person’s food source, whether it be hunting livestock or harvesting crops, which made for an equal balance of energy consumption and expenditure. In today’s world, readily available elevators, escalators, transportation, garage door openers, television remote controls, automobiles, passive entertainment, and uncountable other devices geared towards a decrease in physical activity, have contributed to societies with populations that are in positive energy balance. Other factors such as workplaces with on-site cafeterias and/or vending machines may make for a convenient, yet unhealthy, environment for food choices (5). Socioeconomic factors, such as one’s ethnicity, occupational prestige, education level attained, and income, can also contribute to obesity. Researchers have shown that genetics can play a role in obesity. Heredity affects a person’s susceptibility to obesity. Genes can influence the body’s efficiency to burn and store energy. Conditions such as Bardet-Biedl syndrome and Prader-Willi syndrome can directly cause obesity. With the prevalence of obesity rising in the United States, and numerous factors causing this increase, it is imperative that the scientific research community find practical methods of obesity treatment and prevention. Unfortunately, there are numerous advocates of “fad diets” that are disseminated via the media that prey on uneducated consumers. The vast majority of these weight reduction schemes has proven to have little or no effectiveness and can actually cause more harm than good. 3 Lifestyle habits, including those that contribute to obesity, are among the most difficult to change. Since technologically advanced societies will not return to a hunter- gatherer lifestyle, societal behavior change related to obesity must be addressed promptly, delicately, and above all, practically (4). Purpose and Objectives While much attention has been given to media-driven and ill-advised severe decreases in food consumption to help reverse obesity, significantly less attention has been paid to less drastic changes in eating patterns that might lead to weight loss. Such changes would include the timing of an eating episode