Week 3 Fuel Homeostasis Module

Question 1

1 Calorie=

Answer 1

1000 calories; 1 kcal; 4,180 J; 4.18 kJ

Question 2

what is direct calorimetry?

Answer 2

the heat released from hte total physical combustion of a food

Question 3

rank the following macromolecules in terms of energy released when burned

Answer 3

Fat>Carbs=Proteins

Question 4

why does fat release more energy than carbs or porteins when burned

Answer 4

fats are highly reduced (all C-H bonds). this means their complete oxidation will release more total energy

Question 5

which macromolecule is the most efficient fuel in terms of calories produced/amount of O2 consumed?

Answer 5

carbohydrates

Question 6

what is indirect calorimetry?

Answer 6

estimates caloric yield by measuring the oxygen consumed, CO2 produced and nitrogen eliminated

Question 7

how do you calculate the amount of protein in the body from nitrogen elimination?

Answer 7

16% of protein is nitrogen, multiply the nitrogen excreted by 6.25

Question 8

what is a calorie?

Answer 8

energy needed to raise temperature of one gram of water from 15 to 16DC

Question 9

what is the respiratory quotient

Answer 9

the ratio of the volume of CO2 produced: volume of O2 utilized

Question 10

what is the value of RQ for carbs, protein, fat?

Answer 10

Carbs: 1

protein: .8
fat: .7

Question 11

what will RQ values tell us about feul usage?

Answer 11

the closer the RQ values is to the RQ of a certain fuel source (carbs, protein, fats) the more that fuel source is being used.

Question 12

Ex; if a runner has an RQ of 0.97 at the beginning of a race and then 0.79 towards the end of the race what can be said about his fuel source?

Answer 12

at the start carbs were a major fuel source, towards the end he was using lipids (proteins generally only come into play during starvation)

Question 13

what explains how blood glucose levels are maintained druing exercise?

Answer 13

gluconeogenesis is occuring as well as tapping into glycogen stores

Question 14

As exercise duration progresses from 0 to greater than two hours, what is the change seen in where our bodies are getting energy?

Answer 14

glycogen in skeletal muscle is used first–>glycogen within the liver is used–>fatty acids are oxidized

Question 15

what occurs after glycogen stores are depleted and gluconeogenesis is stopped?

Answer 15

the brain shuts down because glucose is its only form of energy

Question 16

what is energy density?

Answer 16

the amount of energy in a gram of a food item

Question 17

in what three ways do our bodies expend energy?

Answer 17

thermic effect of food energy needed to process food), physical activity (energy needed to move), basal metabolism (energy needed for basic life functions)

Question 18

what percent of out energy goes to basal metabolism?

Answer 18

50-70% (BIGGEST ENERGY EXPENDATURE OF BODY)

Question 19

how is BMR (basal metabolic rate) related to body mass?

Answer 19

BMR is most closely related to lean body mass (muscle), as lean body mass increase the BMR increases

Question 20

what is the BMR when asleep?

Answer 20

10% decrease

Question 21

how much of out energy goes to processing of food (thermic effect of food):

Answer 21

10%

Question 22

how much of our energy goes to physical activity

Answer 22

15-30%

Question 23

what is the difference between resting metabolic rate and basal metabolic rate?

Answer 23

RMR is easier to measure, does not require fasting, and only requires a brief resting period

Question 24

what is the resting energy expenditure?

Answer 24

the resting metabolic rat over 24 hours

Question 25

what is the BMR of males? females?

Answer 25

males: BMR= 1.0 kcal/hour/kg
female: BMR=0.9 kcal/hour/kg

Question 26

how does age, sex, growth, body weight, stress impact BMR

Answer 26

increased age decreases BMR, males have higher BMR, increased weight/height increases BMR, stress increases BMR

Question 27

what is total energy expenditure?

Answer 27

the total (thermogenic effects of food+exercise+basal metabolism) energy used by the body

Question 28

what are the steps for determining total caloric needs of the body?

Answer 28

1. calculate basal energy needs when awake: BMR (kcal/kg/hr)weighthours awake
2. calculate basal energy need when asleep: ten percent decrease in BMRweighthours asleep
3. calculate energy expenditure during exercise Xkcal/kg/hrweighttime
4. calculate thermic effects of food: 10% caloric intake until this point
5. add them together