Greetings TarunTilokani,

I am no expert, but here are my 2 cents.

You have correctly identified the map to the correct answer, so I'll directly expand on how option (A) weakens the argument.

Although the author agrees that migraine headaches are caused by food allergies,

"putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches".

The evidence above made him conclude that there must be some other reason.

As you've correctly figured out what our goal is-


So, lets attack on the reasoning presented.

(A) Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.

Option A correctly points out a flaw i.e. the food you believe you are allergic to might not be the reason for your headache, and you are unable to correctly figure out the food (root cause) that you are allergic to.

Why so? because any allergic would take several days to show an allergic response and thus it becomes a tedious task to figure out the food you are allergic to.

In a way what we have said is - YES! the reason for your headache is FOOD, just that you are unable to figure out which one.



Please let me know if you have any questions, would be happy to expand.

If it is difficult to determine which foods cause migraines, then some foods that cause allergic reactions might not have been demonstrated to do so. Hence, if choice A is true, eliminating foods that have been demonstrated to cause migraines might not eliminate migraines, even if food allergies are the only cause of migraines. Choice A is the best answer.

Neither the fact that some food allergies do not result in migraines (choice B), nor the fact that few allergies result in symptoms more severe than migraines (choice E), explains why restricting one’s diet does not stop migraines. Choice C suggests that migraine sufferers do not naturally avoid the foods at issue. Choice D reiterates the information that eliminating certain foods does not usually solve the problem.
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Pretty straight

For a low mid level student the question is a bit wordy: in particular D is being temptive

But for an advanced student is fairly easy. As it turns out, this question demonstrates how OG is NOT what is a real upper level question during the exam.

Regards
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Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies must exist.

Which of the following, if true, would most weaken the conclusion above?

A.Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.

B.Food allergies affect many people who never develop the symptom of migraine headaches

C.Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.

D.Very few patients have allergic migraine reactions as children and then live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.

E.Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.

Can anyone explain me why 'C' is incorrect? I do find the same topic that had been discussed few years back, but couldn't explore why 'C' is incorrect as the contest was b/w A and D. I got to know why A is correct, but couldn't get the reasoning for why we should make it C as wrong.

As per the conclusion "some other cause of migraine headaches besides food allergies must exist." We can attack to the conclusion to prove that only the food allergy is the cause of the migraine headaches.

A. Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop. [ Correct.] Food is the actual cause and no information which food is allergic

B. Food allergies affect many people who never develop the symptom of migraine headaches.[Not sure food is the cause] Incorrect.

C. Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.[ Patients found the allergic foods, so they can eliminate from their diet] Incorrect.

D. Very few patients have allergic migraine reactions as children and then live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.[Same as C]

E. Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.[Some other cause] Supporting the conclusion.

I got the correct answer by eliminating all other answer choices. But couldn't understand how option A actually weakens the argument? As per my analysis
Conclusion : Obviously, some other cause of migraine headaches besides food allergies must exist.

Weaken the conclusion --->: Food allergies are the only cause for migraines or there is no other cause for migraines

Can someone help me understand how option A weakens the argument GMATNinja egmat

Quote:

Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies must exist.

Which of the following, if true, would most weaken the conclusion above?

Our author states his conclusion that migraines are caused by more than food allergies. He defends this by stating that when eliminating allergic reaction foods from diets, the diet “frequently does not stop headaches.”

To weaken the argument, a possible answer might be that: perhaps it takes a long time for reactions to take effect. So even if the diet commenced last week, the symptoms wouldn’t show until days later and make it appear that the diet is not effective. The answer choice that matches this anticipation is (A).

(A) Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.
This is the correct answer, which matches our anticipated thought.

(B) Food allergies affect many people who never develop the symptom of migraine headaches.
We only care about the people who DO develop migraine headaches. This is an “opposing group” wrong answer and not relevant to our argument.

(C) Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.
This would strengthen the argument because it states that the other cause is “the foods that [patients] most enjoy eating.”

(D) Very few patients have allergic migraine reactions as children and then live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.
This answer choice seems convoluted at first, but it simply tries to explain that it is rare for patients to live migraine free after eliminating foods they are allergic to. If anything, this strengthens the conclusion that migraines are caused by more than food allergies.

(E) Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.
Whether a patient suffers more than headaches is out of scope here.
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The argument is that some other cause of migraines besides food allergies must exist.
This is supported by the fact that a recent test was conducted on those who suffer from migraine headaches in which sufferers were put on diets that eliminated suspected foods believed to have caused said migraines.

We are asked to weaken the argument.
A is correct because if it is true that many common allergic responses to food occur only after several days, then this casts significant doubt over the conclusion drawn from the experiment conducted. The argument does not say anywhere that the researchers controlled for this factor in some way, so if they did not control for it then it would likely lead the researchers to draw an erroneous conclusion.
B is incorrect - we are only concerned with those who develop migraines from food allergies
C is incorrect although it does try to lure people. C is incorrect because the fact that the patients enjoy eating foods that cause them headaches does not negate the fact that when such foods are taken out of the patients' diet it would cease to cause migraines.
D is completely irrelevant - who cares if people who experience migraines are the same ones who don't live migraine-free. That doesn't affect the deduction made from the experiment.
E is incorrect because it doesn't matter whether other symptoms are solicited. We only care about migraine symptoms.
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Hi experts,

Can you please help me in understanding why option A, which says that a delay/difficulty in associating a headache with a food allergy, weakens the conclusion "Obviously, some other cause of migraine headaches besides food allergies must exist".

The premise states that "putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches".

Referring to the bold part, if we are eliminating ONLY those foods that do cause an allergic reaction, why do we even care about the duration of allergic response or how difficult it is to "observe links between specific foods patients eat and headaches they develop" as per option A?

To illustrate my point, if we have demonstrated that food B led to migraine and then removed food B from the patient's diet, why do we care about how difficult it was to identify that food B led to migraine? Shouldn't the migraine just stop had food B (or any other food item, the link of which is demonstrated) been the sole cause of the migraine?

Thanks!

The diets in the passage only eliminate foods which have been demonstrated to cause allergic migraine reactions. These diets were unsuccessful in stopping the patients' migraines, so the author concludes that "some other cause of migraine headaches besides food allergies must exist."

In making this argument, the author is assuming that the only foods that actually cause migraines have been clearly demonstrated to cause migraines.

Consider this example: maybe a certain patient gets migraines every time she eats Flaming Hot Cheetos. So, she goes on a diet that eliminates Flaming Hot Cheetos -- but her migraines don't stop! From this, we might be able to conclude that the Cheetos are not the sole cause of her migraines.

But can we say that all food allergies have been ruled out as the cause? Let's say the patient also eats cucumbers on a regular basis. She is allergic to cucumbers, but doesn't realize this because it take several days for an allergic reaction to appear. By the time she gets a migraine the link to the cucumber is very difficult to observe, as stated in (A).

Cucumbers have not been demonstrated to give the patient migraines, so she does not eliminate them from her diet. The author's conclusion is now severely weakened, because her migraines are, in fact, caused by a food allergy -- just not the one the patient knew about.

(A) is the correct answer.

I hope that helps!
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AndrewN

I know how A is correct. But somehow I am not able to eliminate option C.Why not C here??

People most enjoy eating the food that cause them migraines. They know that this food will cause them migraine but since they love it, they eat that particular food a lot.
If they eliminate that food, they will be free from migraines.

This weakens and says that food is the main culprit.
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warrior1991 Take a look at this line from the question stem "putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches".

It clearly states that even if you remove the food that causes migraine reactions (doesn't matter if the food happens to be a favourite), the headaches do not stop.