Researchers have found that when very overweight people, who tend to have relatively low metabolic rates, lose weight primarily through dieting, their metabolisms 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?

(A) Relatively few very overweight people who have dieted down to a new weight tend to continue to consume substantially fewer calories than do people whose normal weight is at that level.

(B) The metabolisms of people who are usually not overweight are much more able to vary than the metabolisms of people who have been very overweight.

(C) The amount of calories that a person usually burns in a day is determined more by the amount that is consumed that day than by the current weight of the individual.

(D) Researchers have not yet determined whether the metabolic rates of formerly very overweight individuals can be accelerated by means of chemical agents.

(E) Because of the constancy of their metabolic rates, people who are at their usual weight normally have as much difficulty gaining weight as they do losing it.

Could you explain the correct answer? Should I use negating technique to find the answer. Why the use "relatively few" in A. Should this question worth more than 2 minutes 15 seconds?

Thank you very much!

The answer seems to be A.
The reason is that the option A rules the other possibilities of the
conclusion. "relatively few" implies literally no one.

ron or stacey :) - can you pls explain the negation technique here...

if i apply the negation technique on choices a and b .. i am confuse on which one to select (i came down to choice a and choice b)

here are the negated choices...

choice a- relatively few very overweight people who have dieted down to a new weight tend to continue to consume substantially more calories than do people whose normal weight is at that level.....

choice b- the metabolisms of people who are usually not overweight are not able to vary than the metabolisms of people who have been very overweight....

if i negate in this way... choice b is the one which weakens the conclusion...

Consider your negation of B, which I think is quite good,

choice b- the metabolisms of people who are usually not overweight are not able to vary than the metabolisms of people who have been very overweight....

Since the argument has already established that the metabolic rates of the usually overweight don't much vary with dieting, the real force of negating B is the metabolic rates of those who are not usually overweight don't much vary with dieting But this doesn't weaken the conclusion that the usually overweight will regain weight. It doesn't say anything whatsoever about the usually overweight.

Can you confirm what the correct answer is a or b-i tried to look this up but the OA isnt given anywhere.

it should be (a).