According to recent studies, people whose diet is unusually high in pr

Question

According to recent studies, people whose diet is unusually high in protein are more likely to suffer from insomnia than people whose diet contains moderate amounts of protein. It is therefore likely that a diet high in protein is a cause, though perhaps not the only cause, of insomnia.

Which of the following, if true, casts the most serious doubt on the conclusion drawn above?

(A) Diets that are high in protein are often low in foods that help keep the immune system working effectively.

(B) People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.

(C) Reducing the amount of protein in one's diet can be harmful.

(D) People whose diets are unusually low in protein often experience insomnia.

(E) Insomniacs who switched from high-protein diets to more moderate levels of protein intake have reported that the change was so unpleasant that it worsened their insomnia.

KarishmaB · Accepted Answer

Responding to a pm:

Premises:
People with high protein diet are more likely to suffer from insomnia than people with moderate protein diet.

Conclusion:
It is likely that a diet high in protein is a cause of Insomnia.

We don't need to dwell on "perhaps not the only cause" because unless it is specifically mentioned otherwise, we understand that if A is a cause of B, A may not be the only cause. Good that the conclusion mentions it clearly but it was not really needed.

We need to weaken "a diet high in protein is a cause of Insomnia"

A) Diets that are high in protein are often low in foods that help keep the immune system working effectively.
Out of scope. No idea how immune system affects sleep.

B) People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.
This says that people with high protein in their diet have some other characteristics too (e.g. too much consumption of raw foods, stressful exercise regime etc). Some of these could cause insomnia. This means that high protein may not be the cause of insomnia at all. Our conclusion says that P is a cause of insomnia. This tells us that people who have P, also have Q, R and S characteristics. Q/R or S could cause insomnia. So we can say that P may not be a cause at all. The cause is replaced by another cause. Q, R and S may not be additional causes but they might replace P since people with P have Q, R and S too. So we don't really know what is causing insomnia. Hence this weakens our conclusion.

C) Reducing the amount of protein in one's diet can be harmful.
Out of scope.

D) People whose diets are unusually low in protein often experience insomnia.
This says that low protein causes insomnia. It doesn't weaken that high protein causes insomnia. It is certainly possible that high or low amounts of something cause the same problem. Perhaps you need a balanced amount to sleep well. This is just another cause of insomnia and hence doesn't negate that high protein causes insomnia.

E) Insomniacs who switched from high-protein diets to more moderate levels of protein intake have reported that the change was so unpleasant that it worsened their insomnia.

Out of scope. This says that "change" worsened insomnia. It doesn't mean that high protein was not causing insomnia.

Answer (B)

b2bt · Answer

Okay not all very tough question if you read it carefully

It is therefore likely that a  diet high in protein is a cause , though perhaps not the only cause,  of insomnia

A) Diets that are high in protein are often low in foods that help keep the immune system working effectively. -  Do we talk about immune system in clause?  And even after reading this I can say high protein is cause of insomania but this what I have to weaken
B) People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.  Oh! then maybe high protein is not the cause.  Let me hold this one
C) Reducing the amount of protein in one's diet can be harmful. -  Still high protein is the cause of insomnia 
D) People whose diets are unusually low in protein often experience insomnia. -  Again I don't even care if they talk about low protien. Even after knowing the given fact, high protein is the cause of insomnia 
E) Insomniacs who switched from high-protein diets to more moderate levels of protein intake have reported that the change was so unpleasant that it worsened their insomnia.  Again! Still high protein is the cause of insomnia

kinjiGC · Answer

The conclusion is "It is therefore likely that a diet high in protein is a cause".

The option D states "D) People whose diets are unusually low in protein often experience insomnia.", so even low protein can also cause insomnia but it doesn't weaken the above conclusion.

but in the B) there is an alternate reason to cause the insomnia for people having high protein diets. The conclusion totally falls apart.

CrackverbalGMAT · Answer

Hello mahendru1992, Your point is valid. Yet as James pointed out - your doubt can be clarified if you read the stimulus (argument) more carefully. Here are the facts. High protein diet -> insomnia other things can cause insomnia too. Let's say Over exercise, games, salty food, redbull! But the point of the argument is that High protein diets WILL result in insomnia. I.e. Insomnia can be caused by x,y or z BUT eating high protein diets WILL cause insomnia. The assumption is obvious: that there are no other causes at play. option D "People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia." basically breaks this assumption. Let's say people who eat high protein diets are pro-athletes who work out 8 hours a day! Now we realize that these chaps don't just eat high protein diet , but also workout 8 hrs a day. This effectively breaks the assumptions that ONLY high protein diet (for those who eat such diets) is the cause for insomnia. Perhaps the 8 hour workouts is the cause! Hope that cleared you doubt!

Regards, Ajeeth Peo Verbal Trainer, Crack Verbal

semwal · Answer

I WOULD LIKE TO ADD PLEASE.... 
What we are told is that  High Protien causes insomnia........ 
Some of the answer choices give alternate reason for insomnia.....eg Less protein/ moderate protein etc. That cant weaken the argument as its an accepted fact that there can be alternatives.....
ANS  " B" says''' People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.
What is important is that.....  WHAT APPEARS TO BE DUE TO HIGH PROTIEN ......... which is not disputed so far as per the argument ...  MAY ACTUALLY NOT BE SO....  due to those   often other characteristics in common. . When every time HIGH PROTEIN CAUSES INSOMNIA, AND OFTEN ( NOT ALL) TIMES THEY HAVE COMMON CHARACTERISTIC......HOW CAN WE SAY THAT IT IS NOT HIGH PROTEIN BUT THE COMMON CHARACTERISTIC( WHICH OCCURS 51-99% TIMES) THAT COULD HAVE CAUSED INSOMNIA. Every time A goes to a shop... there is a theft. some times or may be often B goes along..... who is the thief if no third person enters the shop..... Obviously A will be the first choice because poor B did not always go.......Does it weaken the argument ???
  ]  PLEASE EXPERTS......IF YOU COULD EXPLAIN.... /   color]

sagarsir · Answer

The conclusion is "a diet high in protein is a cause, though perhaps not the only cause, of insomnia" and talks about high protein intake. Only option A, B and E talk about high protein intake directly. A and E are irrelevant. Hence B. Kudos .. if you like

manojsundar1 · Answer

i chose B as it talked about High Protein along with other characteristics. The conclusion says " It is therefore likely that a diet high in protein is a cause, though perhaps not the only cause, of insomnia".it says that there might be other causes but 
it can be assumed that these causes are apart from High protein consumption.But since the option says that "People whose diet is unusually  high in protein often have other characteristics in common , some of which are likely to cause insomnia",then it becomes that high protein might not have been the one that originally caused insomnia.The other characteristics might have.
hope it helps

samusa · Answer

High protein diet ---> more likelihood for insomnia.Hence, High diet causes insomnia though there may be other causes as well.

I was stuck between B and E.

B- clearly states that there is something else that causes insomnia- ALTERNATE CAUSE.

E- It is just a restatement of the argument , in the sense, that it acknowledges that high protein diet causes insomina and moderate protein diet also causes insomnia.

We are not interested in the relative worsening of the effect.

samusa · Answer

Let us look at the argument afresh for better understanding! ( Also refer to OG 2016 CR 124 - an almost similar question with the desired explanation 8-)

) The argument states the likelihood and then decides causality. It is akin to judging correlation as causation. A positive correlation always strengthens the causality. However, when we study correlation we must have all other variables, except the two under study, as constant. X is positively correlated to Y.----> X may cause Y ( This is essentially the whole argument.This is valid argument in a real world only and only IF OTHER VARIABLES ARE NOT CHANGING but do we know about the other factors or variables that may affect the correlation/causality) Now , how do you weaken the conclusion by proving that OTHER VARIABLES are not constant or may affect the outcome-Such weakening is done by option B. B , simply put, states the X is CORRELATED TO Y and X does not cause Y. B says that please do not mistake correlation for causality. I DONOT MIND KUDOS :-D

tarunk31 · Answer

B is correct.

Correlation/Premise: people whose diet is unusually high in protein are more likely to suffer from insomnia than people whose diet contains moderate amounts of protein.
Conc: a diet high in protein is a cause, though perhaps not the only cause, of insomnia.

Conc. essentially says that a diet high in protein causes insomnia. It doesn't say that another cause cannot cause insomnia. So whoever is taking a diet high in protein will get insomnia. But whoever has insomnia may not have taken a high protein diet.

Let's see what B says.

B. People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.

So if multiple causes of insomnia are observed in the same set of people you cannot attribute insomnia to just one cause(high protein diet). The other factors may have contributed to insomnia rather than a high protein diet. This weaken the conclusion.

Let's look at option D.

D. People whose diets are unusually low in protein often experience insomnia.

diets low in protein is a totally difference cause than a diet high in protein as negation of that cause means diet not high in protein which does not imply a diet low in protein. SO you are essentially saying that another cause causes insomnia. Conclusion says that and hence this option supports rather than weaken.

I think other options can be easily discarded.

tarunk31 · Answer

smartguy595

Conc says that high protein diet causes insomnia. It also says that high protein diet may not be the only cause.

So basically to weaken this conclusion we need to provide additional information that says that high protein diet is actually not a cause and it's just a correlation as observed in the premise. So if you say that people who have insomnia have other attributes, in addition to high protein diet, that are likely to cause insomnia then it strengthens the correlation and weakens the causation.

Option B says that more than one cause of insomnia may be present in the same person. So that means you cannot say that one cause, high protein diet, caused insomnia. So option B strengthens the correlation and weakens the causation. And this question asks us to weaken the causation.

abrakadabra21 · Answer

According to recent studies, people whose diet is unusually high in protein are more likely to suffer from insomnia than people whose diet contains moderate amounts of protein.

It is therefore likely that a diet high in protein is a cause, though perhaps not the only cause, of insomnia.

Which of the following, if true, casts the most serious doubt on the conclusion drawn above?

B) People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.

E) Insomniacs who switched from high-protein diets to more moderate levels of protein intake have reported that the change was so unpleasant that it worsened their insomnia.

I dont agree with OA.

Comparsion is between people whose diet is unusually high in protein and people whose diet contains moderate amounts of protein.

Now B only addresses one side of the story. That People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia. We don't know about people whose diet contains moderate amounts of protein. "though perhaps not the only cause" also strengthen that there could be other reasons. We already know fro the premises that there are other reason of Insomania.

What E does is :-

high-protein diets => Moderate levels of protein

Now technically Insomania should get better ( what pateints feel is psychological thing) but it's not doing that so defenietely you can't pin point it to High protein diet. E seems correct option.

Further evidence:
in-a-recent-study-a-building-trade-group-found-208221.html

Between D & E, D is OA. Because it deals with the comparative issue. Although E introduce another factor "Aesthetic", it is not as strong as D.

D.Compared with those in the other two regions, many more of the fireplaces in the Southeast use natural gas as a fuel instead of wood, producing very little heat but making them much cheaper and easier to use than wood stoves.

E.Although once an important part of home heating, fireplaces have now largely become status symbols for fashionable homeowners.

warriorguy · Answer

I think the real challenge is between B and D.

B -> People whose diet is unusually high in protein often have other characteristics in common, some of which are likely to cause insomnia.

So it can be deduced that high levels of protein is not the cause of insomnia (maybe?) It introduces an element of doubt and hurts the conclusion a bit. Does act like a weakener.

D --> People whose diets are unusually low in protein often experience insomnia.

It is possible that both cases can exist together. The stem does identify that high levels of protein is one of the cause of insomnia among others. Maybe low levels of protein is also a cause.

arunavamunshi1988 · Answer

Hi Karishma,

I have a question here. Here, as per my analysis, the assumption is 'the study, which we are talking about is mostly representative of this conclusion.' What if the study is not representative. Perhaps, the study might be wrong, means the amount of protein may not be an indicator for insomnia. If we can prove that the study mentioned here is not the representative for the conclusion or something is missing in the study, then the conclusion is weakened. I guess 'D' gives us most reason to doubt on the study. Perhaps, the study did not take into account the consequences when there is a lower content of protein in food, thus weakening the conclusion.

On the other hand, it is clearly written in the conclusion that protein may not be the only cause of insomnia. So proving some other cause(as does option B) as the reason for insomnia may not be a good choice. Please let me know if I am missing anything.

eddy8700 · Answer

There is some other common factor in the high protein diet that causes insomnia .
So high protein may not have caused insomnia
thus weakning the conclusion
Answer is B

KarishmaB · Answer

This is a premise and should be taken to be true: Studies show that people with high protein diet have insomnia more often than those with moderate protein diet.
So the study compared high protein vs moderate protein. Since it found a link between high protein and insomnia, we can conclude that high protein might be a cause of insomnia.
Option (D) says that low protein also seems to be linked to insomnia. This is certainly possible. It doesn't question our previous conclusion. Any imbalance in the amount of protein could cause insomnia. It doesn't weaken our conclusion.

Option (B) does weaken and here is why: Our conclusion that high protein causes insomnia is based on the study that found that people with high protein diet are more likely to suffer from insomnia. What if these same people also have other common features such as they all exercise too much. If these features are likely to cause insomnia, it is possible that high protein diet has nothing to do with causing insomnia. What we are assuming is a link between high protein and insomnia, could actually be a link between too much exercise and insomnia (as an example).

Think about it:

There were 100 people in a study. We found that 50 consume a high protein diet and 50 consume a moderate protein diet. Many of the 50 with the high protein diet are found to suffer from insomnia. Among the other 50, the rate of occurrence was the same as the average rate.
Now this might make us conclude that high protein diet leads to insomnia.

But what if we are told that the 50 with high protein diet are also the 50 who exercise too much? Now is it possible that insomnia is actually linked to too much exercise and not to high protein diet? Sure. It does bring that question in mind. It certainly casts doubt on our conclusion. So this is your option (B).

Option (D) has nothing to do with the study. It doesn't bring our conclusion into question. Low protein diet could be another factor leading to insomnia.

thr3at · Answer

Hello KarishmaB

I have a doubt if I say A is the cause of B, as you said, it mean that C can also be a cause of B. Then How option B weakens this argument.

Please explain.

RiyaJ0032 · Answer

Hello,

MartyMurray 
 GMATNinjaTwo 
 DmitryFarber

had a doubt in (E)

just wanted to know that,

if protein was the cause of insomnia
then if one switches to moderate protein diet, shouldn't it reduce the levels of insomnia?

can't we infer this?

and because it did not reduce the levels of insomnia, can we infer that maybe protein was not the cause of it and something else was?

can some expert please help with this
Thank you!

JuniqueLid · Answer

This is a classic CORRELATION > inferred causal relationship question so choosing (B) seems natural in the GMAT setting. However, what is unique in this question is the qualifier "perhaps not the only cause" in the conclusion -  does it play a critical role or we can generally ignore it if it pops up somewhere else in a different question?

If we see this qualifier as a integral part of a conditional conclusion, then (B) wouldn't cast as much doubt on the conclusion - it simply offers possibilities of alternative causes, which the original conclusion already admits could exist.

Any thought is welcome and much appreciated.

According to recent studies, people whose diet is unusually high in pr

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According to recent studies, people whose diet is unusually high in pr

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