LSAT Explanation PT 26, S3, Q15: A person's dietary consumption of cholesterol

LSAT Question Stem

The statements above, if true, most strongly support which one of the following? 

Logical Reasoning Question Type

This is a Most Strongly supported question. 

Correct Answer

The correct answer to this question is C. 

LSAT Question Complete Explanation

Let's first analyze the information in the passage. The passage tells us that a person's dietary consumption of cholesterol and fat is an important factor in determining their blood serum cholesterol levels. It states that serum cholesterol levels rise proportionally to increased cholesterol and fat consumption until a threshold is reached. Once this threshold is exceeded, serum cholesterol levels rise only gradually, even with dramatic increases in consumption. This threshold is one fourth the consumption level of cholesterol and fat in today's average North American diet.

Now, let's identify the question type and what it's asking us to do. This is a Must Be True (MSS) question, meaning we need to find the answer choice that is most strongly supported by the information provided in the passage.

Let's evaluate each answer choice:

a) The threshold can be lowered by lowering the dietary consumption of cholesterol and fat.

- The passage does not provide any information on whether the threshold can be lowered, only that it is one fourth the consumption level of cholesterol and fat in today's average North American diet. Therefore, we cannot conclude that lowering dietary consumption will lower the threshold.

b) People who consume an average North American diet cannot increase their consumption of cholesterol and fat without dramatically increasing their serum cholesterol levels.

- This statement is not supported by the passage, as it states that once the threshold is exceeded, serum cholesterol levels rise only gradually, even with dramatic increases in consumption.

c) People who consume half as much cholesterol and fat as in the average North American diet will not necessarily have half the average serum cholesterol level.

- This is the correct answer choice. The passage tells us that serum cholesterol levels rise proportionally to increased cholesterol and fat consumption until the threshold is reached. If a person consumes half as much cholesterol and fat as the average North American diet, they would still be above the threshold (as the threshold is one fourth the consumption level). Since serum cholesterol levels rise only gradually beyond the threshold, we cannot say that they will have half the average serum cholesterol level.

d) Serum cholesterol levels cannot be affected by nondietary modifications in behavior, such as exercising more or smoking less.

- The passage does not discuss nondietary modifications in behavior and their effect on serum cholesterol levels, so we cannot conclude this from the information provided.

e) People who consume less cholesterol and fat than the threshold cannot reduce their serum cholesterol levels.

- This statement is not supported by the passage. The passage states that serum cholesterol levels rise proportionally to increased cholesterol and fat consumption until the threshold is reached. This implies that if a person consumes less cholesterol and fat, their serum cholesterol levels would also proportionally decrease.

In conclusion, the correct answer is choice C, as it is most strongly supported by the information provided in the passage.