CH 8 ENERGY BALANCE occurs when energy intake energy expenditure stable body weight Energy imbalance Positive energy balance energy intake energy expenditure body weight increases Negative energy balance energy intake energy expenditure body weight decreases 3500 cal 1 lb adipose tissue Hunger Physiological drive to consume food Satiety Physiological response to having eaten enough feeling full Gastric bypass bypassing a segment of the small intestine helps eat less food and decreases nutrient digestion and absorption Tryptophan an amino acid needed for normal growth in infants and for nitrogen balance in adults Appetite Psychological longing or desire for food Food aversion dislike Long term and persistent Food craving want Calorie rich foods Timing of cravings Influence of sensory factors Total energy expenditure TEE Basic involuntary life functions BMR influenced by body comp age sex nutritional status genetics etc Resting metabolic rate Resting energy expenditure REE Harris Benedict equation 1 Basal metabolism energy required for basic life functions 50 70 of TEE 2 Physical activity energy required for movement 15 30 of TEE Amount is variable influenced by type of activity and body size 3 Thermic effect of food TEF energy required to process food 10 of TEE Adaptive Nonexercise activity thermogenesis Assessing TEE Calorimetry Indirect Exchange of respiratory gases Stable isotopes especially labeled water Mathematical formulas Amount and types of foods consumed Protein content Direct HOW ARE BODY WEIGHT BODY COMPOSITION ASSESSED Underweight 17 18 or 18 5 BMI Healthy weight 18 or 18 5 25 BMI Overweight Excess weight 25 30 BMI Obese Excess fat 30 34 BMI Hydrostatic weighing Density in water Dual energy X ray absorptiometry DEXA Gold standard Bioelectrical impedance Conduction of electrical currents Skinfold thickness Thickness of subcutaneous fat Visceral Adipose Tissue Apple shaped fat around organs Greater risk for weight related health problems Metabolic syndrome Subcutaneous Adipose tissue Pear shaped fat directly under skin Waist Circumference 1 Stand w feet 6 7in apart 2 Relaxed and breathing out 3 Midway b w top of hip bone and bottom of rib cage 4 Tape loose enough for 1 finger width b w tape and body Central Adiposity Males circumference of 40in or more Females circumference of 35in or more Eating habits Societal influences Fast food Serving sizes Visual cues Variety of foods increases intake Sociocultural factors Psychological factors Abundant food and slimness is valued Media athletes and social networks family dynamics personality traits biological genetic factors ATHLETE TRIAD 1 Disordered eating inadequate nutrient and energy intake low body weight and fat 2 Menstrual Dysfunction low body weight and fat disrupt reproductive hormones causing irregular or loss of menstruation 3 Osteopenia loss of menstruation leads to low bone density increase risk of stress fractures Physical activity recommendations Sedentary activities no more than 2hrs of TV Recommended activity levels for young people 150min wk 3 5 days Aerobic activity 2 3 days Resistance training Genetics influences our susceptibility 50 of risk is determined by genetics or epigenetics Twin studies Obesity genes ex Mice Leptin ob ob mouse Leptin Receptor db db mouse ob ob mouse receives leptin from db db mouse ob ob mouse loses weight db db mouse doesnt change weight cause it cant respond to leptin ob ob mouse receives leptin from normal mouse ob ob mouse loses weight normal mouse doesnt change weight normal mouse receives large amounts of leptin from db db mouse normal loses weight db db mouse doesnt change weight cause it can t respond to leptin Leptin communication with the brain hormone in hypothalamus Leptin is produced by adipose tissue lets us know when we re full When body fat decreases less leptin reaches brain anabolic neurotransmitters are released increase catabolic neurotransmitters are suppressed decrease increase food intake decreased energy expenditure and weight gain positive energy balance Slow and steady weight loss lose 10 of your body weight THE BEST APPROACHES TO WEIGHT LOSS Health weight loss and maintenance programs Setting reasonable goals Choosing nutritious foods in moderation Moderation and wise choices Hunger and satiety cues Increasing energy expenditure by daily activity 150min wk Aerobic 3 5d Resistance 2 3d Characteristics of successful weight loss keeping the weight off DOES MACRONUTRIENT DISTRIBUTION MATTER Not necessarily good diets 1 High Carb Low Fat 2 Low Carb High Fat Ketogenic high weight loss in short duration HOW DO EATING DISORDERS DIFFER FROM DISORDERED EATING Disordered eating Unhealthy eating patterns Common causes Eating disorders Extreme disturbances in eating behaviors Physically and psychologically harmful Complex behaviors Anorexia Nervosa AN Irrational fear of weight gain Distant b w actual and perceived body weight Self worth Rituals 15 or less ideal body weight 2 types 1 Restricting type Restrictive dieting pursuit of thinness 2 Binge eating purging type Restrictive dieting binge purge guilt shame pursuit of thinness May be reversible Decline in estrogen Reproductive function bone health Death Health concerns Bulimia Nervosa BN Food as a coping mechanism More common than AN Rituals Bingeing Compulsive consumption Purging Forms Binge eating disorder BED Prevalent Most Common Binges provide escape