ENERGY BALANCE - ENERGY BALANCE: STUDY GUIDE I. RULE # 1:...

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ENERGY BALANCE: STUDY GUIDE I. RULE # 1: Energy balance depends Only on 2 phenomenons: Calories coming in and calories leaving: Change of weight is caused by a change of energy intake or a change in expenditure. a. ∆ Weight= ∆ Energy in - ∆ Energy out b. We can’t measure ATPs of food, so how do we know how much energy there is in the food? i. Estimating energy content of food: 1. Measured in Calories (really kilocalorie)- the amount of heat required to raise 1 cc of water 1 degree centigrade 2. Joules (not used in U.S.)- the amount of work done by a force of 1 newton acting over a distance of one meter. a. Looks at energy as a means of doing work 3. Calories and Joules are interchangeable- 1 Kcal=4.2 KJoules ii. Measure the Calories by using a bomb calorimeter : 1. Has been around since the mid-18 th century 2. measures the amount of heat released by food when it is burned 3. STEPS: a. Place dried sample of food in secure chamber b. Fill cavity with pure oxygen c. Add a spark by exploding it d. Food blows up inside the combustion chamber e. There is water around the chamber- you measure the rise in the temperature of the water, which tells us how many calories were given off in that food 4. All kcal labels derived from this method 5. Carbohydrates =4.15 kcal/gm 6. proteins = 5.65 kcal/gm 7. fats=9.45 kcal/gm 8. alcohol= 6.93 kcal/gm 9. The reason they’re not the same value is because we lose lots of energy in process of absorbing the food. 10.
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ENERGY BALANCE - ENERGY BALANCE: STUDY GUIDE I. RULE # 1:...

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