Fats and performance

Question 1

After what time are carbohydrates a limiting factor in exercise?

Answer 1

> 90 mins

Question 2

Which is an alternative to delay fatigue?

Answer 2

to increase the capacity to oxidise fat

Question 3

What are some advantages of lipids over CHO?

Answer 3

• Greater energy density
• Most efficient way of storing energy in limited space
• More ATP per molecule (147 vs 38)

Question 4

What is the primary function of white fat (WAT)?

Answer 4

energy storage (triglycerides)

Question 5

What are the two different WAT depots?

Answer 5

• Subcutaneous (scWAT)
• Visceral (vWAT)

Question 6

Explain brown fat (BAT)

Answer 6

Metabolically active tissue, oxidises CHO and lipids to generate heat.
Central nucleus and a high density of mitochondria

Question 7

Explain beige fat (brite)

Answer 7

• Only found in scWAT
• Generate energy in the form of heat, contributing to thermogenesis
• High degree of spasticity, revert to WAT in the absence of stimuli

Question 8

True or False
Lower-body adipocytes (scWAT) tend to expand via hyperplasia

Answer 8

True

Question 9

True of False
Upper-body adipocytes (vWAT anterior abdominal wall region) expand via hypertrophy

Answer 9

True

Question 10

What is hyperplasia?

Answer 10

Increase in the number of fat cells

Question 11

What is hypertrophy?

Answer 11

Increase in size of cells

Question 12

What are some differences in MFO and fatmax between groups?

Answer 12

• MFO was greater in trained groups
• Absolute MFO were greater in males than females
• Fatmax was greater in females compared to males
• Prior CHO feeding tends to reduce MFO and Fatmax

Question 13

Increases in vWAT are correlated with:

Answer 13

• Impaired glucose tolerance
• Increased insulin resistance

Question 14

Increases in scWAT are correlated with:

Answer 14

• Decreased metabolic risk

Question 15

True or False
Long term exercise increases fatty acid oxidation in human WAT

Answer 15

True

Question 16

which exercise intensity oxidise the most fat?

Answer 16

65% VO2max in trained
55-72% VO2max well conditioned cyclist
43-61% VO2max in obese individuals

Question 17

Where are the intramuscular triglycerides (IMTG) located?

Answer 17

adjacent to mitochondria in trained muscle

Question 18

What is associated with insulin resistance in obese/sedentary individuals?

Answer 18

Intramuscular triglycerides (IMTG)

Question 19

What is the main source of fat oxidation at moderate to high exercise intensities?

Answer 19

Intramuscular triglycerides (IMTG)

Question 20

What is the difference between maximal fat oxidation and Fatmax?

Answer 20

• Maximal rate of fat oxidation (MFO) (g.min-1) is the point at which the body’s use of fatty acids (FAs) for energy is at its highest.
• Fatmax: exercise intensity at which MFO occurs (% VO2max)

Question 21

What are the main differences in exercise-induced adaptations in WAT compared with BAT in man?

Answer 21

• long term exercise increases fatty acid oxidation in human WAT
• Glucose uptake: Exercise increases glucose uptake in WAT, but does not affect glucose uptake in BAT.
• Endocrine activity: Exercise increases endocrine activity in both WAT and BAT.

Question 22

Where does ketogenesis occurs?

Answer 22

In mitochondria of liver cells

Question 23

Briefly outline the factors that affect IMTG use for fuel during exercise

Answer 23

Exercise duration
Training status
Diet
Hormones

Question 24

What are the 3 ketone bodies synthesised in ketogenesis?

Answer 24

• acetoacetate (AcAc)
• beta-hydroxybutyrate (BOHB)
• acetone

Question 25

Explain some facts about Keto Diet (KD)

Answer 25

- <50g CHO/day 60-80% kcal from fats and 1.2g.kg/d protein - keto adaptation may take 2-4 weeks - increased fat oxidation but impairs glycolytic pathways - no performance benefit - may be effective to reduce body weight and fat mass (in the short term)

Question 26

Explain fat adaptation

Answer 26

- may result in metabolic alterations favouring fat oxidation - not improved exercise performance

Question 27

What is ketogenesis?

Answer 27

A catabolic pathway of metabolism. Fatty acids and certain ketogenic amino acids are broken down to derive energy by alternative means. Ketone bodies are produced in the process.

Question 28

Reason for why endurance training results in increased capacity to oxidise fats during mild-moderate intensity exercise

Answer 28

Regular aerobic exercise promotes training induced adaptations such as increased activity of lipoprotein lipase an increased capillarisation in trained muscle