BPK 110 Human Nutrition:Current Issues Topics for Lectures 8a

Transcription

1 BPK 110 Human Nutrition:Current Issues Topics for Lectures 8a 1. Energy Balance 2. Energy Input and Bomb Calorimeters 3. Three Components of Total Energy Expenditure 4. Estimating your Daily Energy Needs

2 Learning Objectives To describe energy balance and macronutrient energy balances To understand and describe how energy contents of the 3 macronutrients are determined with a bomb calorimeter To name and describe the 3 components of human energy expenditure To complete a sample calculation of your own estimated daily energy intake need To complete an energy balance 2

3 1a. Energy Balance: is when Food Energy (eaten) = Energy Expended (3 parts) If Energy In = Energy Out? Body weight is stable. If Energy In > Energy Out? Body weight increases. If Energy In < Energy Out? Body weight decreases.

4 1b) Macronutrient Balances: Caloric Values of Energy Nutrients or Macronutrients All determined with a Bomb Calorimeter We can calculate an energy balance for each Macronutrient Macro-Nutrient or e.g. CHO in - CHO out 4 kcal/g e.g. Fat in - Fat out 9 kcal/g 4 kcal/g (kcal = 1000 cal = 1 Cal)

5 We measure energy in calories or Joules With a Small c 1 Calorie (Cal) = 1 kilocalorie (kcal)=1000 calories With a BIG C Energy gives the ability to do work A Calorie

6 2) Energy In and the Bomb Calorimeter -a Bomb Calorimeter determines amount of heat or energy a food releases when burned -food caloric or energy values are given at the DIET ANALYSIS PLUS website -gives the Energy In of the Energy Balance Equation

7 3) Three Components of Human Total Energy Expenditure (TEE) 25 50% physical activity 5 10% thermic effect of food 50 65%

8 Basal Μetabolism 50-65% of TEE -Basal Metabolic Rate (BMR) -usually measured in the a.m. -after a hour fast -takes about 30 min to measure

9 Table 9-3 Factors that Affect BMR

10 Estimating Physical Activity Energy Expenditure from oxygen consumption during physical activity different activities have different caloric costs Appendix E in S,W &P ver 3 for different daily activities Physical Activity: on average is 25-50% of TEE

11 Thermic or Thermal Effect of Feeding (TEF) TEF is 5 to 10% of energy value of a meal or all food consumed each day energy cost of digestion and absorption of food estimated from oxygen consumption after a meal

12 4. Estimating your Daily Energy Needs: 3 steps Step 1. Calculate the Basal Metabolic Rate: Females: 0.9 kcal/kg/hour x body weight in kg Males: 1.0 kcal/kg/hour x body weight in kg -e.g. If Ms. N.R. Gee weighs 50 kg, what is her basal metabolic caloric need per day? 50 kg x 0.9 kcal/kg/hour = 45 kcal/hour 45 kcal/hour x 24 hour/day in 1080 kcal/day So, 1080 kcal of energy is needed each day for Ms. N.R. Gee s basal metabolic processes

13 Step 2a. Estimate energy expenditure from physical activity as a % of BMR Men Women Sedentary 25-40% 25-35% Light 50-70% 40-60% Moderate 65-80% 50-70% Heavy % % Exceptional % % Ms. N.R. Gee s basal energy requirement is 1080 kcal/day Lower Limit: 40% of 1080 = 432 kcal/day Upper Limit: 60% of 1080 = 648 kcal/day

14 Step 2b. Detailed Estimate energy expenditure from physical activity (optional for EE calculation) Sample Calculation on p 379 S,W&P Enter Physical Activity Factor or see App. E

15 Step 3. Estimate Ms. N.R. Gee s Thermic Effect of Feeding (TEF) Ms. NR Gee s Energy In is 1920 kcal of food per day And her TEF is 10% of 1920 kcal/day This gives her a TEF of 192 kcal/day Since TEF is 5-10% of caloric value of food consumed (above we chose to use 10% in the calculation)

16 A summary of Ms. N. R. Gee s Total Energy Expenditure (TEE): 1. Her BMR= 1080 kcal/day 2. Her Physical Activity Energy Expended = 432 to 648 kcal/day 3. Her Thermic Effect of Feeding = 192 kcal/day 4. Her TEE is between 1704 & 1920 kcal/day kcal kcal kcal = 1704 kcal/day kcal kcal kcal = 1920 kcal/day

17 Ms. N. R. Gee s Total Energy Expenditure Balance: Her TEE is between 1704 & 1920 kcal/day kcal kcal kcal = 1704 kcal/day kcal kcal kcal = 1920 kcal/day Her Food Intake is 1920 kcal/day Her Total Energy Balance is 1920 kcal/d kcal/d =0 Or Her Total Energy Balance is 1920 kcal/d kcal/d =+216

18 Summary Lecture 8a 1. Energy Balance 2. Energy Input and Bomb Calorimeters 3. Three Components of Total Energy Expenditure 4. Estimating your Daily Energy Needs