Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through...
GMAT Critical Reasoning : (CR) Questions
Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolism generally remain unchanged. They will thus burn significantly fewer calories at the new weight than do people whose weight is normally at that level. Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate.
The conclusion of the argument above depends on which of the following assumptions?
Passage Analysis:
| Text from Passage | Analysis |
| Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolism generally remain unchanged. |
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| They will thus burn significantly fewer calories at the new weight than do people whose weight is normally at that level. |
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| Such newly thin persons will, therefore, ultimately regain weight until their body size again matches their metabolic rate. |
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Argument Flow:
The argument starts with research about how metabolism works during dieting, then compares the calorie-burning rates of formerly overweight vs naturally thin people, and concludes that this difference will cause weight regain.
Main Conclusion:
People who lose weight through dieting will eventually gain it back because their metabolism stays low.
Logical Structure:
The argument assumes that people's eating habits and calorie intake will remain constant or return to normal levels. If formerly overweight people permanently ate much less than naturally thin people, they wouldn't necessarily regain weight despite having slower metabolisms.
Prethinking:
Question type:
Assumption - We need to find what must be true for the conclusion to hold. The conclusion is that newly thin people will regain weight until their body size matches their metabolic rate.
Precision of Claims
The argument makes specific claims about metabolic rates staying unchanged during dieting, calorie burning differences between formerly overweight and naturally thin people, and inevitable weight regain. We need assumptions that bridge these facts to the conclusion.
Strategy
To find the assumption, we'll look for ways the conclusion could fail even if all the stated facts are true. The argument tells us that formerly overweight people burn fewer calories than naturally thin people at the same weight, but jumps to concluding they'll definitely regain weight. What must be assumed for this jump to work?
This choice says that most formerly overweight people don't permanently eat substantially fewer calories than naturally thin people of the same weight. This is exactly what the argument must assume! The argument tells us formerly overweight people burn fewer calories than naturally thin people, then concludes they'll regain weight. But wait - what if these people permanently ate much less to compensate for their slower metabolism? Then they wouldn't necessarily regain weight. The argument assumes this doesn't happen - that people won't maintain dramatically reduced calorie intake long-term. This assumption is essential for the conclusion to work.
This talks about whether naturally thin people's metabolisms can vary more than formerly overweight people's metabolisms. But the argument doesn't need to assume anything about whether metabolisms can vary - it's based on the research finding that formerly overweight people's metabolisms generally remain unchanged. Whether other people's metabolisms are more flexible doesn't matter for this specific conclusion about weight regain.
This suggests daily calorie burn depends more on daily consumption than current weight. But this actually contradicts the argument's foundation, which is based on metabolic rates being tied to the person's history (formerly overweight people maintaining low metabolic rates). The argument assumes metabolism is relatively stable, not highly responsive to daily intake.
This is about whether researchers have studied chemical ways to speed up metabolism in formerly overweight people. The argument doesn't need to assume anything about what researchers have or haven't studied regarding chemical interventions. The conclusion is based on current research findings about natural metabolic patterns during dieting.
This discusses whether naturally thin people have equal difficulty gaining and losing weight due to constant metabolic rates. But the argument isn't making any claims about naturally thin people's weight change difficulties - it's specifically focused on what happens to formerly overweight people after they diet down to a lower weight.