Diet Designing : BMR,SDA and Calorie intake calculation.
- 1. Energy requirement of normal person Energy required for • BMR-Basal Metabolic Rate • SDA- Specific Dynamic Action • Extra energy expenditure for physical activities are to be considered while calculating energy needs of a person.
- 2. BMR • Definition: energy required by an awake individual during physical, emotional and digestive rest. • It is the minimum amount of energy required to maintain life or sustain vital functions like heart beat, circulation of blood, brain function, respiration etc. • The metabolic rate during sleep < BMR.
- 3. • BMR is measured directly by heat evolved, or indirectly by the volume of oxygen consumed and carbon dioxide released per unit time. Factors affecting BMR: Age: During period of active growth, BMR increases. Max BMR attained by 5 yrs of age. and later as age increases, BMR decreases
- 4. Sex: Males have higher BMR than females Temperature: Cold climates --- increases BMR Exercise: Increases BMR -- cardiac out put increases. Starvation --- decreases BMR
- 5. Fever: 1°C rise in temperature – increase BMR 12%. Thyroid Hormones: Hyperthyroidism --- increases BMR Hypothyroidism --- decreases BMR Normal Value of BMR for adult male is 34 to 37 kcal/m2 /hour. BMR for adult is fixed at 24 kcal/kg body wt/day.
- 6. SDA • SDA refers to increased heat production or increased metabolic rate following the intake of food (diet induced thermogenesis). • This is due to expenditure of energy for digestion, absorption and active transport products of digestion. And also due to synthesis of glycogen and TAG from absorbed biomolecules.
- 7. • This energy is trapped from previously available energy, so that actual energy from food is lesser than that of theoretical calculation. • SDA can be considered as an activation energy needed for a chemical reaction. This activation energy needed to be supplied initially.
- 8. • Eg: 250 g of carbohydrate should produce 250*4 = 1000 kcal. But before this energy is trapped, about 10%, 100 kcal is drawn from the existing reserves of the body. • Thus the net production of energy is only 1000 – 100 = 900 kcal. • If the person wants to get 1000 kcal, he should take food worth 1100 kcal. • Thus, additional calories, equivalent to SDA has to be added in the diet.
- 9. • SDA for proteins = 30% lipids = 15% carbohydrates = 5% Hence for mixed diet, an extra 10% calories should be provided to account for the loss of energy as SDA.
- 10. Energy calculation General Principles • The ideal body weight: For adult male is 48 Kg for a height of 153 cm, ±1.25 Kg for every cm For adult female is 45 Kg for a height of 153 cm, ±1.0 Kg for every cm Protein Requirement: Adults: 1g per Kg body weight. Children: 2 g per Kg body weight. Pregnant & lactating female: 2 g / Kg body wt.
- 11. Calorie requirement • Depends on age, sex, height, weight, health status, physical activity and occupation. • For an adult with ideal body wt, the calorie requirement is taken as 30-35 Kcal/Kg body wt. • For sedentary worker, lower value (30 Kcal) is considered and for heavy worker highest value (35 Kcal) are prescribed. • The average an Indian weight considered as 55-65 Kg, the average calorie requirement will be 1700 to 2300 Kcal per day.
- 12. • During preganancy and lactation period an additional allowance of 300 k cal is necessary. Specific Dynamic Action (SDA): extra energy to be supplied for SDA (10% of requirement) • Ratio: Carbohydrate, Proteins and Fats to be supplemented in the ratio of 60:20:20.
- 13. • The steps in prescription of balanced diet 1. Calorie requirement. 2. Proximate principles. 3. General composition of food. 4. Determine the items of food.
- 14. • 1. calorie requirement: • Average 60 Kg sedentary man, calorie required is 60*30= 1800 Kcal • For SDA, 1800*10% = 180 kcal • Total calorie requirement is = 2000 Kcal/day. First step in the prescription of diet Energy required + SDA 2000 kcal Protein (60*1g) 60 g Calcium 400 mg Iron 25 mg
- 15. 2. Proximate Principles 60 g protein will give 60 x 4 = 240 kcal Total requirement is 2000 kcal Carbohydrates + fats should provide, 2000 – 240 =1760 kcal. 20% of calories must provided by fats ie 1760 = 350 kcal.
- 16. Prescription of diet, second step Proteins 60 g Fats 35 g Carbohydrates 350 g Calories 2000 Kcal Calcium 400 mg For supply 350 kcal, 350/9 = ~ 35 g of fats to be supplemented in the diet. Remaining 1400 kcal must provide by carbohydrates, 1400/4 = 350 g of carbohydrates required in the diet.
- 17. 3. General composition of food This step is to calculate how these proximate principles are supplied as common foodstuffs. The simplified version is given in table below.
- 18. Balanced diet for adult man Food type Sedentary work Moderate work Heavy work Veg Non veg Veg Non-Veg Veg Non-Veg Cereals (g) 400 400 475 475 650 650 Pulses (g) 70 55 80 65 80 65 Green leafy veg (g) 100 100 125 125 125 125 Other veg 75 75 75 75 100 100 Roots&Tubers 75 75 100 100 100 100 Fruits 30 30 30 30 30 30 Milk 200 100 200 100 200 100 Fats& oils 35 40 40 40 50 50 Meat& flesh --- 30 ----- 30 ---- 30 Eggs --- 30 ------- 30 ------ 30 Sugar 30 30 40 40 55 55 Groundnut ----- ------ ------ ------ 50 50
- 19. • Step-4, Determination of food items • “Food exchange” is used to calculate proximate principles. • Foods with similar nutrient composition are grouped together. • Mutual supplementation of Cereals and Pulses • A judicious combination of cereals and pulses provide all the essential amino acids. • Pulses lack in Met. • Cereals lack in Lysine. • The food with combination of cereals and pulses will supply good quality proteins.
- 20. • 5-step: Three meals per day • The total quantities of proximate principles, thus calculated are divided into breakfast, lunch and supper.