ENERGY BALANCE 8 NOVEMBER 2010

Introduction to energy (nrg) balance   Constant spend and refuel- excess stored Not all excess nrg in is stored-some extra nrg used for maintaining extra body weight Slow weight loss desirable –otherwise yo-yo effect - diet and exercise is the key

Energy in a) Food composition   b) Food intake Hunger Satiation Satiety Overiding hunger and satiety signals

Energy in Food composition Use of oxygen to break bonds- O2 as a nutrient concept  

Energy in     Food intake Hunger Depends on food content of stomach in part —reduced amounts of food —smaller stomach—less demand; — larger amounts of food — larger stomach—larger demand   Receptors in gi tract determine whether nutrient intake has been high or low

ENERGY INTAKE CONTINUED FOOD INTAKE CONTINUED Satiation and Satiety   Satiation-When to stop eating Satiety- Do not start eating again Overiding hunger and satiety signals Boredom, stress, time of day, availability, sight, taste of food

Energy out Components of energy expenditure   Basal metabolism Physical activity Thermic effect of food- Adaptive thermogenesis

Energy out continued 50 % dietary Kcal to ATP and rest radiates as heat ATP 50 % to work and 50 % to heat there only 25 % of kcal used   Basal metabolism Just to keep the doors open and the heat and lights on   -calculated as weight (lbs) x 10 cal/lb

ENERGY OUT CONTINUED Physical activity body mass and activity (duration, frequency and intensity).   Thermic effect of food- nutrients-dat, metabolise and store Adaptive thermogenesis Adaptation to stress (eg cold or exercise) - body needs extra energy to build tissues

GRAND TOTAL ENERGY OUT   2200 kcal/day for females 2900 kcal/day for males

Body weight, body composition and health Body weight and its standards   Body weight and its standards Weight within range recommended for height and sex 10 % below std-underweight 10-20 % over -overweight > 20% obese

correct 18.5-24.9 overweight > 25- 29.9 obese > 30 Body weight, body composition and health continued   Body weight and its standards continued B) BMI Kg/m2 underweight- <18.5 correct 18.5-24.9 overweight > 25- 29.9 obese > 30

Body weight, body composition and health continued BODY FAT AND ITS DISTRIBUTION   PERCENT BODY FAT- FOR GOOD HEALTH MALES FEMALES < 40 YEARS 22 32 > 40 YEARS  25 35

Body weight, body composition and health Continued FAT DISTRIBUTION IS IMPORTANT TOO   WAIST/HIP > 0.9 IN MEN AND > 0.8 IN WOMEN -APPLE SHAPE- PROBLEMS WITH LDL AND ATHEROSCLEROSIS IN MEN AND WOMEN PEAR SHAPE REDUCES RISK OF ATHEROSCLEROSIS Males –40 inch waist Females-35 inch waist

Health risks associated with body weight and body fat Health risks of underweight Preserve lean tissue against wasting Infertility Give birth to unhealthy infants      Health risks of overweight Atherosclerosis(stroke)   Diabetes-type 2 diabetes already discussed  Cancer- weight and weight gain tied in here- not fully understood why- may be related to hormones

SUPPLEMENTS-ALL CLAIMS FALSE MA HUANG-HERB CONTAINING EPHEDRINE ALLEGED TO INDUCE WEIGHT LOSS CHROMIUM PICOLINATE- ALLEGED TO BURN FAT SPIRULINA-POWDER FROM ALGAE – ALLEGED TO SUPPRESS APPETITE GUAR GUM-ALLEGED TO SUPPRESS APPETITE VIA ABSORBING WATER AND BLOATING STOMACH GYMNENA SYLVESTRE PLANT-CLAIMED TO BLOCK SUGAR ABSORPTION