Fat Burning Fundamentals and Core Concepts 3

Question 1

What happens to blood insulin levels during fasting that promotes fat burning?

Accepted Answer

Insulin drops, reducing inhibition of lipolysis

Answer

Falling insulin during fasting removes its inhibitory effect on hormone-sensitive lipase, allowing fat cells to release stored fatty acids.

Question 2

Which substrate does the brain preferentially use for fuel when glucose is scarce, such as during prolonged fasting?

Accepted Answer

Ketone bodies

Answer

During prolonged fasting, the liver converts fatty acids into ketone bodies (beta-hydroxybutyrate and acetoacetate) that cross the blood-brain barrier and fuel the brain.

Question 3

Which of the following describes the 'respiratory exchange ratio' (RER) value closest to 0.7?

Accepted Answer

The body is burning mostly fat

Answer

An RER near 0.7 indicates predominant fat oxidation because fat metabolism produces approximately 0.7 molecules of CO2 per molecule of O2 consumed.

Question 4

Which type of adipose tissue is metabolically active, generates heat, and is found in higher amounts in newborns and cold-adapted adults?

Accepted Answer

Brown adipose tissue

Answer

Brown adipose tissue (BAT) is packed with mitochondria and uncoupling protein-1 (UCP1), which dissipates the proton gradient as heat instead of ATP.

Question 5

What physiological event is known as 'hitting the wall' or 'bonking' during endurance exercise, and how does it relate to fat burning?

Accepted Answer

Depletion of muscle glycogen forcing greater reliance on slower fat oxidation

Answer

When glycogen stores are depleted, the body must rely more heavily on fat oxidation, which is slower and less ATP-efficient, causing a dramatic drop in pace.

Fat Burning Practice Test

Fat Burning Practice Test

Fat Burning Fundamentals and Core Concepts 3