Metabolism
Feasting Feasting adds to body stores of carbohydrate and fat Excess carbohydrate used to fill glycogen stores excess glucose stored as fat Excess fat stored as fat Excess protein remove N and store as fat
Fasting – Glycogen Available Draw upon stores during: fasts (even short-term) during exercise Energy stores used: Carbohydrate – stored as ________________ Fat
Fasting – Glycogen Available Liver glycogen blood glucose energy for all cells Muscle glycogen muscle glucose energy for muscle cells Fat stores fatty acids in blood provide energy for all cells, but brain and CNS
Fasting – Glycogen Stores EMPTY Only protein and fats are available as a source of energy See board!
Estimating Energy Needs Body uses energy for: Basal metabolism Thermic effect of food Physical activity
Basal Metabolism Basal metabolism Energy needed to maintain the body at complete rest (physical, emotional, and digestive) Largest component of daily energy expenditure
Basal Metabolism Basal Metabolic Rate (BMR) # kcal burned per hour per kg body weight
Basal Metabolism BMR impacted by: Lean body mass More LBM, the higher your BMR More fat, the lower your BMR Age and gender (related to LBM) BMR slows with age BMR higher in males
Basal Metabolism Height Fever raise BMR Taller, thinner people have a higher BMR More surface area to support Fever raise BMR 10 F fever raises BMR by 7% Fasting and malnutrition lower BMR
Basal Metabolism Smoking and caffeine raise BMR Stress raises BMR
Thermic Effect of Food TEF – energy needed to digest, absorb, transport, and metabolize nutrients Smallest component of daily energy expenditure ~ 10% caloric intake
Physical Activity Physical Activity – energy needed to support voluntary activity Energy required impacted by: Muscle mass Body weight Nature of activity Duration, intensity, frequency
Energy Expenditure Summary To maintain energy balance, energy input must balance energy expenditure Expend energy to: support basal metabolism] process foods (TEF) support physical activity