🔑 Key Definitions
Obesity: Excessive body fat accumulation; influenced by genetic, metabolic, behavioral, and environmental factors
BMR (Basal Metabolic Rate): Energy expenditure at rest; varies individually and can decrease with dieting
Brown Adipose Tissue: Specialized fat that generates heat; burns calories for thermogenesis rather than storage
Field Dependence: Cognitive style where eating is strongly influenced by external cues rather than internal hunger signals
BMR (Basal Metabolic Rate): Energy expenditure at rest; varies individually and can decrease with dieting
Brown Adipose Tissue: Specialized fat that generates heat; burns calories for thermogenesis rather than storage
Field Dependence: Cognitive style where eating is strongly influenced by external cues rather than internal hunger signals
🧠 Causes of Obesity
- Genetic Factors: Heredity influences body weight set point, metabolism, fat distribution
- Environmental Factors: Food availability, portion sizes, sedentary lifestyle, cultural norms
- Field Dependence: External cues (sight/smell of food, time of day) override internal hunger signals
- Impulse Control: Difficulty resisting immediate food rewards; poor self-regulation
- Depression: Emotional eating as coping mechanism; some antidepressants increase appetite
📊 Metabolic Factors
- BMR Variability: People differ in baseline metabolic rate; some burn calories more efficiently
- Diet-Binge Cycle: Restrictive dieting lowers BMR, making regain easier; yo-yo dieting
- Brown Adipose Tissue: "Good fat" that burns calories for heat; more active in lean individuals
- NE Role: Norepinephrine activates brown fat thermogenesis; increases energy expenditure
📊 Behavioral Patterns
- External Eating: Eating triggered by environmental cues rather than physiological hunger
- Set Point Defense: Body resists weight loss by lowering metabolism and increasing hunger
- Restraint Theory: Chronic dieting can paradoxically lead to overeating episodes
💡 Exam Tips
- Obesity = complex: genetics + environment + behavior + metabolism
- BMR decreases with dieting - makes weight loss progressively harder
- Diet-binge cycle: restrict → lower BMR → regain weight faster
- Brown fat BURNS calories (thermogenesis), white fat STORES calories
- NE activates brown fat - increases energy expenditure
- Field dependence = eating controlled by EXTERNAL cues, not internal hunger