BMR.pptx

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1. DETERMINATION OF ENERGYVALUE OF FOOD Mrs. MANIMEGALAI.S Assistant Professor Department of Nutrition FSM&D SACWC,CUMBUM

2. Energy: the capacity to do work, such as moving or heating something Calorie: The unit used to measure energy a kilocalorie is a unit of energy What is enerGy ?

3. Antoine Lavoisier  (1743-94) showed that O 2  consumption increased during work, exposure to cold and during digestion (specific dynamic effect), and was lower during fasting (basal metabolism). He was the  father  of calorimetry . Antoine- LAURENT Lavoisier

4. Bomb calorimeter

5. Weight of wheat taken = 2g Weight of water in outside vessel = 3000g Water equivalent of the calorimeter = 500g Initial temperature of the water = 24 c Final temperature of the water = 26 c Rise in temperature = 2 c Heat gained by water & calorimeter = 3500x2=7000cal or 7 kcal 1g wheat produces = 3.5 kcal example

6. 1g of CHO - 4.10kcal 1g of F at - 9.45kcal 1g of P rotein - 5.65kcal The energy value derived from bomb calorimeter

7. The amount of energy available to the body from a given amount of nutrient Digestibility coefficient- Carbohydrate – 0.98 Fat – 0.95 Protein – 0.92 Bomb calorimeter- F ibre is utilizing Physiological fuel value

8. CHO and fat- No energy loss in metabolism Protein – Energy lost as urea- incomplete oxidation Loss- 1.3kcal/g Carbohydrate – 4 kcal Fat – 9 kcal Protein – 4 kcal Atwater bryant factors or Physiological fuel value

9. The volume of oxygen required to burn a known weight of the food. The amount of oxygen consumed in burning 1g of pure CHO, fat or protein can be determined. Benedict’s oxy-calorimeter

10. 1g of CHO- 0.8lit of oxygen- complete oxidation- 4.1kc 1g of fat- 2.2lit of oxygen- complete oxidation- 9.5kcal 1g of protein- 1.2lit of oxygen- complete oxidation- 5.5kcal Indirect calorimeter

11. The energy required to maintain basal metabolism (BMR 60-65%) The energy required to power physical activity (physical activity 25-30%) The energy is released as a result of the thermic effect of food (thermic effect of food 5-10%) Total energy requirement

12. The amount of energy required to carry on the involuntary work of the body Functional activities- brain, heart, liver, kidney and lungs Secretory activities of glands Peristaltic movement Oxidation in tissues Maintenance of muscle tone Maintenance of body temperature Basal metabolic rate

13. Surface area- basal heat loss is proportional to the skin surface and basal heat production is directly proportional to the surface area Sex – women have 6 to 10% less BMR than men Age- highest during the first 2yrs of life, declines in childhood, accelerates slightly in adolescence, thereafter declines throughout the life Factors influencing the bmr

14. Sleep- 10% lower than in the waking state Body temperature- increase in BMR by 13% for increase in body temperature more than 37 c (98.6 F) Endocrine glands- thyroid gland, BMR increases 75-100% in hyperthyroidism and reduced by 30-40% in hypothyroidism, growth hormones, epinephrine Factors influencing the bmr

15. Pregnancy- last trimester, BMR increases from 15-25% State of nutrition- prolonged fasting and chronic under nutrition reduce BMR Physical activity- higher BMR in the night following a day of strenuous muscular work Factors influencing the bmr