Logical Reasoning

PT126 · S3 · Q22 In a study, one group of volunteers

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In a study, one group of volunteers was fed a high­-protein, low-carbohydrate diet; another group was fed a low-protein, high-carbohydrate diet.

Evidence

In a study, one group of volunteers was fed a high-protein, low-carbohydrate diet; another group was fed a low-protein, high carbohydrate diet.

Both diets contained the same number of calories, and each volunteer’s diet prior to the experiment had contained moderate levels of proteins and carbohydrates.

After ten days, those on the low-carbohydrate diet had lost more weight than those on the high-carbohydrate diet.

Conclusion (thus)

The most effective way to lose body fat is to eat much protein and shun carbohydrates.

Evaluate

This conclusion is very strong. To know for certain the most effective way to do anything is nearly impossible—the unknown is typically too vast. Furthermore this argument conflates correlation with causation. Finally, there’s a term shift—losing weight is not the same as losing body fat.

22.

Which one of the following, if true, most weakens the argument above?

  1. Correct

    A low-protein, high-carbohydrate diet causes

    Why this is right

    This points to the term shift in the argument’s conclusion and changes the results of the study. It suggests that those on the high-carbohydrate diet might have lost more body fat than was initially indicated. How much more though is unclear. But if it’s more than the low-carbohydrate diet, the argument’s conclusion would be false.

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

    65% picked this

  2. Many people who consume large

    Too Weak

    Without knowing that these people shunned carbohydrates or that they refrained from eating absurd amounts of food, they are not a relevant counter example.

    17% picked this

  3. A high-protein, low-carbohydrate diet will

    Strengthen

    This makes the conclusion more likely to be true by providing a further unknown amount of body fat that could be lost in addition to that lost from weight loss.

    8% picked this

  4. In the experiment, the volunteers

    Strengthen

    This suggests the weight loss by the high-carbohydrate diet cannot all be attributed to the diet, making the amount of weight loss attributable to the diet something less than was appreciated before. This makes it more likely that a low-carbohydrate diet is the most effective way to lose body fat.

    6% picked this

  5. Many of the volunteers who

    Out of Scope

    What happens after one loses weight is not relevant when determining the most effective way to lose body fat in the first place.

    4% picked this

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