Chapter 04 - Energy Balance in the Body

Question 0

List and briefly describe the three main factors that contribute to the net combustible energy of food.

Answer 0

1. The macronutrient’s heat released with combustion.
2. The macronutrient’s percentage of digestibility.
3. The amount of nitrogen lost in the urine.

Question 1

Explain what a Calorie is and how it relates to nutrition.

Answer 1

Calories represent the amount of heat required to raise the temperature of one kilogram of water by 1 degree centigrade.

1 Calorie = 1000 calories
We measure calories by combusting food in a bomb calorimeter.

Question 2

Why is counting kcals from food unpredictable?

Answer 2

Calorie values on food labels are mere approximations.
Other factors:
1. Resistant starches
2. Data are outdated
3. Analytical methods are imprecise
4. Product variety
5. Soil and growing conditions
6. Ripeness at the time of harvest
7. Animal's diets
8. Length of storage
9. Preparation method and cooking time

our digestion and excretion rates

Question 3

List the five general metabolic components. Identify key points for each.

Answer 3

1. Basal metabolic rate (BMR)
   Minimum level of energy expenditure needed to maintain vital functions. Without movement or digestion
2. Resting metabolic rate (RMR)
   Similar to BMR, but more easily collected
3. Thermic effect of feeding (TEF)
   The amount of increased metabolism for digestion and absorption. The process of heat production in the body.
4. Exercise activity
   The energy used to perform purposeful activity.
5. Non-exercise activity thermogenesis
   The unplanned, low intensity daily physical activity.

Question 4

How does oxygen consumption relate to energy cost and metabolism?

Answer 4

There is a direct, mathematical relationship. 4.7 Calories are transferred when 1 liter of oxygen is consumed in the oxidation of carbohydrate. Mixture provides 4.82 Calories.

Question 5

What are the main predictive equations used for RMR? What is the variability? What range is considered “acceptable”?

Answer 5

Harris-Benedict
Owen
Mifflin
Acceptable if within 10% of the actual measured value
High variability between these.

Question 6

What is RQ? What does it represent? How is it calculated?

Answer 6

Respiratory quotient
Ratio of the volume of carbon dioxide exited to the volume of oxygen consumed in a given period of time.
RQ = CO2 produced/VO2 consumed

Question 7

What factors beyond hunger and exercise influence energy balance?

Answer 7

Individual environmental factors, genetic factors, hormonal responses, digestive/absorptive capacity, and more

Question 8

How does substrate utilization differ between exercise intensities?

Answer 8

Higher intensity, shorter duration, more carb breakdown

Lower intensity, longer duration, more fat

Question 9

Does the macronutrient content of a meal alter what substrate we use during exercise? Why or why not?

Answer 9

Higher carb meal will lead to greater carb use during exercise,
Higher fat and protein intake will lead to greater fat use during exercise.

Question 10

If someone is out of shape and only exercising at a very low intensity, will consuming a recovery beverage with high amounts of simple carbs help them lose body fat? Explain your answer.

Answer 10

When carbs are in abundance the body prefers to use carbs and not fat.

No

Question 11

List and describe the four bodily functions that can be altered via drastic energy imbalances?

Answer 11

Reproductive functions
Deficit - estrogen and testosterone production becomes limited, reduced fertility, irregular periods, impotence
Too high- interferes with hormones

Cognitive
Imbalance can impair cognitive functions, can affect mood

Metabolic
Calorie low, RMR decreases

Repair and restorative functions
Can impair resynthesis of muscle and liver glycogen, protein synthesis

Question 12

What roles do vitamins and minerals play in energy production?

Answer 12

Co- factors and co-enzymes in ATP process
Iron- effects oxygen transport
Vitamin B3 can limit NAD and NADH activity