PrepTest 130, Section 3, Question 9
Typically, people who have diets high in saturated(48 more words not shown)
Which one of the following,(9 more words not shown)
- APeople who add(15 more words not shown)
- BAdding unsaturated fat(14 more words not shown)
- CDiet is the(10 more words not shown)
- DTaking steps to(14 more words not shown)
- EIt is difficult(19 more words not shown)
Reading the argument
At first we have an association: people with diets high in saturated fat tend to have more heart disease. Is the fat responsible, or do these people also tend to smoke, exercise less, or eat fewer vegetables? That first sentence alone doesn't answer the causal question.
The next sentence gives us more: people who replace saturated fat with unsaturated fat reduce their risk. That supports a connection between the dietary change and heart health. We'd still want to know whether other habits changed too, but there is a more immediate problem in the conclusion.
Replacing isn't the same as adding. The successful change described in the premise has two parts: less saturated fat and more unsaturated fat. The conclusion keeps only the increase in unsaturated fat. What if reducing saturated fat is what matters? Someone could add unsaturated fat while continuing to consume all the saturated fat they ate before, and the premise wouldn't tell us what happens to that person's risk.
What we’re looking for
We're asked for an assumption that most helps justify the reasoning. One way to help would be to establish that the added unsaturated fat itself reduces the risk. Let's see whether an answer addresses the gap between the change in the evidence and the change the author recommends.
Working the answers
- ACorrect
This connects the recommendation to the evidence by a different route: adding unsaturated fat will also lead people to eat less food high in saturated fat. The conclusion's 'adding' now involves the reduction that made it look different from 'replacing.' That makes the evidence about replacement much more relevant to the recommended change.
- B
Other health benefits don't establish a reduced risk of heart disease. Unsaturated fat might benefit some other aspect of health while leaving this risk unchanged. The argument is about this particular outcome, so general improvements aren't enough to repair it.
- C
Even if diet is the most important factor, we still need to know what this specific dietary change does. Diet's overall importance doesn't establish that adding unsaturated fat without reducing saturated fat lowers the risk. Nor does the conclusion need diet to outrank every other factor; it only needs the proposed change to help.
- D
Preventing heart disease might increase life expectancy, but that tells us the value of achieving the goal. It doesn't tell us whether adding unsaturated fat achieves it. We need support for the step from dietary change to reduced heart-disease risk.
- E
Replacing one type of fat with another isn't necessarily switching to a diet with very little total fat. E describes a different change. Also, difficulty making a change doesn't tell us its effect if a person makes it. The missing connection concerns the result of the recommended diet, not how easy it is to follow.
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