very overweight people

[gmathanoifall2010]

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!

[parthatayi]

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.

[addy199]

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...

[mschwrtz]

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.

[asth678]

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

[RonPurewal]

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).

[sgyoung12345]

What's the logic behind why the answer could not be C?

I was looking for an answer that dealt with calorie consumption (since I figured that was where the premise-conclusion needed to be bridged). Although I understand the logic behind A, when I was solving I just leaned towards C.

If I negate and say that the amount of calories that person burns in a day is determined more by the weight instead of the calories consumed...then wouldn't this weaken the argument? Because if calories burned is based on weight, then because the dieters have gotten down to a certain weight as normal people at that weight then they'll burn the same # of calories and wouldn't regain?

I read another explanation that basically said the logic behind my explanation is right...but that because now I'm saying dieters will burn the same # calories this actually conflicts with what's mentioned in the passage (...burn significantly fewer calories at the new weight than do people whose...). But I wanted to see if this conflicting of info is why C should be eliminated.

[jlucero]

I'd say you wouldn't even have to refute C. If we are looking for an assumption, we are looking for something that must be true. If C were true, then, as others have mentioned, it goes against the argument.

Note that we only look to negate when we are trying to prove that something MUST be true. When the opposite of the assumption is true, the argument should no longer stand. This is a case where the answer choice CAN'T be true, otherwise the argument wouldn't stand.

[chetan86]

Hi,

Could you please explain why A is correct?

Option A is trying to save the relationship between metabolic rate and body weight by saying that newly thin person has not started consuming more calories so intake of calories is not responsible for gained weight?

Thanks!!

[RonPurewal]

let's say that, once an overweight person has lost lots of weight, he/she needs to eat X calories per day to maintain the new (lower) weight. (according to the passage, people who have not been overweight can maintain their weight while eating more than X calories.)

choice (a) basically just says "not very many of those people will manage to eat only X calories per day". can you see why this is a necessary assumption?

[chetan86]

let's say that, once an overweight person has lost lots of weight, he/she needs to eat X calories per day to maintain the new (lower) weight. (according to the passage, people who have not been overweight can maintain their weight while eating more than X calories.)

choice (a) basically just says "not very many of those people will manage to eat only X calories per day". can you see why this is a necessary assumption?

Hi Ron,

Thanks a lot for your reply.

Could you please confirm whether my understanding is correct?

Options A is necessary assumption to make provided reasoning true. Otherwise, if newly thin people continue to eat fewer calories and still gain weight then author's conclusion gets weaken. A is basically filling the gapes between premises and conclusion.

Thanks!!!

[tim]

Looks right. Remember to use the negation test - if you take the opposite of A, the conclusion is impossible. That's how you know A is necessary!

[RonPurewal]

Could you please confirm whether my understanding is correct?

Options A is necessary assumption to make provided reasoning true. Otherwise, if newly thin people continue to eat fewer calories and still gain weight then author's conclusion gets weaken. A is basically filling the gapes between premises and conclusion.

Thanks!!!

that's not how it works.
the red thing is actually impossible: if they continue to eat reduced calories, they won't gain weight.
the argument basically says that, in the main, these people won't continue to eat super-low calories.

[RonPurewal]

the negation of choice (a) would be "lots of these people will continue to eat super-low calories".
if that's true, then the author is going to be wrong, since those people won't regain weight.

[chetan86]

Could you please confirm whether my understanding is correct?

Options A is necessary assumption to make provided reasoning true. Otherwise, if newly thin people continue to eat fewer calories and still gain weight then author's conclusion gets weaken. A is basically filling the gapes between premises and conclusion.

Thanks!!!

that's not how it works.
the red thing is actually impossible: if they continue to eat reduced calories, they won't gain weight.
the argument basically says that, in the main, these people won't continue to eat super-low calories.

Hi Ron,

Thanks for identifying my mistake.

the negation of choice (a) would be "lots of these people will continue to eat super-low calories".
if that's true, then the author is going to be wrong, since those people won't regain weight.

Now I can see how and why A is correct.
Thanks a lot for your great explanation.