PrepTest 126, Section 1, Question 24
Advertisement: Researchers studied a group of people trying(65 more words not shown)
The reasoning in the advertisement(15 more words not shown)
- Aeating foods that(27 more words not shown)
- Ba few of(27 more words not shown)
- Cthe people in(30 more words not shown)
- Dsome people in(24 more words not shown)
- Epeople who eat(33 more words not shown)
Reading the argument
Maybe the successful dieters were doing something else that helped them lose weight.
The study finds an eating pattern among the people who lost the most: more calories from protein than carbohydrates and a larger meal early in the day. That could be useful information. But the pattern might go along with another difference. Perhaps these people consumed fewer calories overall. Perhaps they were more active.
Imagine a group of cyclists who tend to eat this way and also lose weight. Their activity could help explain the weight loss, while their meals simply reflect the same lifestyle. The study's association wouldn't by itself tell us that copying the eating pattern would produce the result.
What we’re looking for
The advertisement nevertheless promises weight loss to anyone following its diet. For the flaw question, I'd initially look for an overlooked cause or some other reason the eating pattern isn't responsible. Let's check what the choices actually establish, especially how directly they bear on the promise.
Working the answers
- A
Feeling fuller isn't itself a result about losing weight. We'd need to add a chain of assumptions about how fullness changes eating and how that changes weight. A doesn't establish that people following the advertised approach fail to lose weight, or that the proposed approach can't help.
- B
People losing weight through a different eating pattern don't show that this pattern fails. The advertisement says its diet will work, not that it is the only way to lose weight. Successful nighttime carbohydrate eaters would challenge an exclusivity claim, but that isn't the claim being made.
- C
This sounds close to the activity explanation I predicted, so it's worth slowing down. It says increasing activity was associated with greater average weight loss across the protein/carbohydrate groups. Activity could therefore matter in addition to diet.
But the guarantee concerns losing some weight, not losing the most weight. It could still be that following the eating pattern produces weight loss and adding activity produces even more. C doesn't establish that anyone following the relevant pattern loses no weight. D gets much closer to the promise we're evaluating.
- DCorrect
Some people had the two eating features the advertiser relies on and lost no weight. That's the result the advertisement overlooks when it moves from the most successful dieters to a promise of success for anyone following its approach.
My first objection concerned other causes of weight loss. D exposes the stronger problem with the guarantee: the study includes people with the cited pattern who didn't get the promised result. A pattern among the biggest losers doesn't establish that everyone with that pattern will lose weight at all.
- E
This offers a possible advantage for eating the biggest meal earlier: nighttime big-meal eaters tend to snack more and take in more calories overall. It doesn't expose a failure of the advertised pattern. If anything, it gives the advertiser another possible reason to favor earlier meals, without proving the guarantee.
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