All Sample Questions

Ketogenic Diet and Elevated Ketone Bodies 1

Question

Vignette:

A 25-year-old male presents to the emergency department with severe abdominal pain, nausea, and vomiting. He reports that he recently started a ketogenic diet and has been strictly consuming high-fat, low-carbohydrate foods for the past week. His blood tests show that his glucose levels are significantly lower than normal, while his ketone body levels are significantly elevated.

Question:

Given this patient’s diet, which of the following is the most likely explanation for his elevated levels of ketone bodies?

Choices

A. Increased glycolysis

B. Increased lipogenesis

C. Increased gluconeogenesis

D. Increased glycogenolysis

E. Increased beta-oxidation of fatty acids

Answer

E. Increased beta-oxidation of fatty acids

Explanation

The ketogenic diet is a high-fat, low-carbohydrate diet that forces the body to burn fats rather than carbohydrates for energy. When carbohydrate intake is significantly reduced, the body has to rely on the breakdown of fat stores for energy. This process is known as beta-oxidation. As a result of beta-oxidation, acetyl-CoA is produced. When the amount of acetyl-CoA exceeds the capacity of the TCA cycle, it leads to the formation of ketone bodies, which can be used as an alternative energy source by many tissues, including the brain. This explains the patient's elevated ketone body levels. The other choices, including increased glycolysis (A), lipogenesis (B), gluconeogenesis (C), and glycogenolysis (D), would not directly lead to an increase in ketone bodies.