Obesity and Eating Disorders Overview

Obesity and Eating Disorders

• Obesity prevalence among U.S. adults (20-74) more than doubled from 14.5% (1976-1980) to 35.7% (2009-2010).
• This increase affected all demographics (men, women, various age groups, racial/ethnic backgrounds, and socioeconomic statuses).
• Severe obesity (BMI ≥ 40) is increasing faster than other obesity classifications.
• Disordered eating includes abnormal eating behaviors affecting physical and mental health.
• Examples of disordered eating include anorexia nervosa and bulimia nervosa.
• Obesity and eating disorders were historically studied separately, with obesity seen through a medical lens and eating disorders through a psychological/psychiatric lens.
• Both obesity and eating disorders share factors like appetite regulation issues, body image concerns, and overlapping risk factors.
• Treatment approaches for both often include nutrition therapy, behavior modification, physical activity, medication, and sometimes surgical interventions.

Causes of Obesity

• Obesity occurs when calorie intake consistently exceeds calorie expenditure, leading to fat accumulation (energy imbalance).
• Obesity is a metabolic disease influenced by multiple factors beyond willpower.
• Individual susceptibility to weight gain is influenced by genetics and environmental factors.
• The body regulates its weight around a natural "set-point" range (set-point theory).
• The body resists changes outside this range, making sustained weight loss challenging.
• Calorie reduction may cause the body to slow its metabolism to conserve energy.
• An interaction of an obesogenic environment, unhealthy behaviors, and genetic predispositions contributes to weight gain.

Obesogenic Environment

• An obesogenic environment encourages high calorie intake while discouraging physical activity.
• Factors in an obesogenic environment include abundant, low-cost, high-calorie foods; increased soft drink and snack consumption; more meals eaten outside the home; larger portion sizes at restaurants; and reduced physical activity due to labor-saving devices and sedentary lifestyles (e.g., TV, video games, computers).

Genetics and Obesity

• Genetics influence how the body responds to calorie intake.
• Factors include basal metabolic rate (BMR), body fat distribution, and response to overeating.
• Individuals respond differently to weight loss efforts due to genetic variations.
• Adoption studies and BMI heritability estimates (40-70%) suggest a genetic basis for obesity.

Complications of Obesity

• Obesity is linked to higher mortality and morbidity, including metabolic disorders (diabetes, high cholesterol, fatty liver disease), respiratory disorders (obstructive sleep apnea, GERD), musculoskeletal problems (vertebral disc disease, osteoarthritis), and certain cancers.
• Abdominal obesity increases the risk of metabolic syndrome, coronary heart disease, and type 2 diabetes.
• Obesity increases risks of complications during and after surgery, and during pregnancy, labor, and delivery.
• Obesity can contribute to mental health issues (low self-esteem, negative self-image, depression).
• Obesity-related social impacts include stigmatization, social isolation, and discrimination.

Goals and Challenges in Obesity Treatment

• Ideal treatment goals include short-term weight loss (1-2 pounds per week) and long-term maintenance of a healthy BMI.
• Lifestyle modification for sustainable weight loss requires substantial and often long-lasting changes in diet and physical activity.
• Weight regain after initial success is common due to metabolic adaptations.
• Even a modest 5-10% weight reduction can improve blood pressure, cholesterol, blood sugar levels, and reduce type 2 diabetes risk.
• Preventing further weight gain may be a more realistic goal for some individuals than weight loss, and active intervention remains beneficial even when weight loss itself is challenging.

Evaluating Motivation for Weight Loss

• Motivation significantly impacts the success of weight loss efforts.
• Imposing treatment without individual motivation risks resistance and reduces future success.
• Assessing motivation involves identifying readiness for change and tailoring the approach accordingly.
• Stages of motivation for change include precontemplation, contemplation, preparation, action, maintenance, and relapse/termination.

Weight Management with Nutrition

• Weight management requires a comprehensive lifestyle approach.
• Key components include nutrition therapy, physical activity, behavior modification, and, for high BMI or serious comorbidities, pharmacotherapy or surgery.

Nutrition Therapy

• Calorie reduction strategies target a deficit of 500-1000 calories daily (approximately 1-2 pounds of weight loss per week).
• Metabolic adaptations (body lowering its calorie expenditure as weight decreases) may require further calorie reductions.

Calorie Intake Recommendations

• Calorie guidelines vary by gender and activity levels.
• Recommended intake is 1000-1200 kcal/day for women, and 1200-1600 kcal/day for men and active/heavier women.

Diet Plans for Weight Loss

• Very-Low-Calorie Diets (VLCDs): Provide approximately 800 kcal/day for rapid weight loss, but may cause nutrient deficiencies.
• Low-Carbohydrate Diets (Atkins-Type): Deplete glycogen stores and potentially induce ketosis to suppress appetite.