Some fast food chains have responded to concerns that their products a

A 20 second reading and the correct answer is D

Explanation:-

Fast food restaurants have started selling low carb and low fat food.
Why? Because fast food restaurant want to let the customer know even though they are selling fast food, it is not unhealthy.

In other words we have to weaken this line:- "Fast food restaurant have added low carb and low fat because they want to sell healthy food"

A. Nutritionists are still strongly divided over whether a low carbohydrate diet or a low fat diet is better for helping people to lose weight.
WRONG:- If that was the case then restaurant need not to add low carb and low fat food because its benefit are not established.

B. Many items that are neither low fat nor low carbohydrate remain highly popular at the fast food chains that have begun to offer more healthful options.
WRONG:- This option tells us that people will be stupid. Even though healthy food is available these idiots will buy unhealthy food. Does not weaken restaurants claim. They are selling healthy food. They have kept their end of bargain. Now its for the customers to buy those healthy options.

C. Those who tend to be the most concerned about the harmful effects of fast food on Americans' health would be unlikely to eat at these chains even if the chains provided low fat and low carbohydrate menu options.
WRONG:- Well, This option says some people will not buy at all whether restaurants provide healthy or non healthy food. They are the demographic that the restaurant has no concern with. These people hate fast food restaurants and fast food can do nothing to lure them.

D. Fast food chains have found that they can charge significantly higher prices for menu offerings that are perceived to be healthful and nutritious.
CORRECT :- This gives an alternate reason why restaurants have added low carb and low fat options. Not because these restaurants care about peoples health but because such fancy low carb and low fat options are sold at a much higher price. HIGHER PRICE=HIGHER PROFIT. SO actually all this drama by the restaurants is for profit and not for peoples health.

E. Consumer pressure has led several fast food chains to eliminate "jumbo-sized" menu offerings because of the perception that these offerings promote poor health and obesity.
WRONG:- This may be or may not be a weakener because it requires a long jump of assumption that people asked to stop jumbo size food. then restaurants thought ohh. people like to be healthy and then restaurants add healthy options. THIS OPTION REQUIRES A UNNECESSARY ASSUMPTION.
IT is also wrong because it does not talk about the reason why can't the company just remove all jumbo food and continue with small portion of the same food. WHY DOES THE RESTAURANTS HAVE TO INTRODUCE SPECIAL FANCY LOW CARB AND LOW FAT FOOD.


ANSWER IS D

Some fast food chains have responded to concerns that their products are contributing to a perceived obesity crisis by offering customers a wide assortment of new "low carbohydrate" and "low fat" menu offerings. Clearly, the reason for these menu changes is a desire on the part of these chains to prove that fast food does not necessarily have to be unhealthful junk food.

Which of the following most seriously undermines the explanation offered above for the behavior of the fast food chains?

A. Nutritionists are still strongly divided over whether a low carbohydrate diet or a low fat diet is better for helping people to lose weight.
B. Many items that are neither low fat nor low carbohydrate remain highly popular at the fast food chains that have begun to offer more healthful options.
C. Those who tend to be the most concerned about the harmful effects of fast food on Americans' health would be unlikely to eat at these chains even if the chains provided low fat and low carbohydrate menu options.
D. Fast food chains have found that they can charge significantly higher prices for menu offerings that are perceived to be healthful and nutritious.
E. Consumer pressure has led several fast food chains to eliminate "jumbo-sized" menu offerings because of the perception that these offerings promote poor health and obesity.

The "explanation" mentioned in the question refers to the " desire on the part of these chains to prove that fast food does not necessarily have to be unhealthful junk food" , keyword being desire.

Option D debunks this by proving that the Fast Food companies did not make menu changes because they wanted to prove something, but because they could charge higher for the food. Therefore Option D is correct

conclusion says the reason for menu change is the concerns on chains, the concern the chain wants to prove.
what is if some other reason is their to change menu.
D shows different motto to change.

kaplan official explanation:
Identify the Question Type

Since it asks to undermine an explanation, this is a Weaken question.

Untangle the Stimulus

The stimulus contains a causal argument: the desire to prove that fast food is not junk food caused the fast-food chains to introduce the low-fat and low-carb menu items. The author assumes that the fast-food restaurants changed their menus for this reason and no other.

Predict the Answer

Predict that the correct answer will present a different possible cause for the introduction of the new items.

(D) provides an alternative explanation: if the chains believe they can make more money on these new items, that may be reason enough to introduce them, regardless of any health claims.

(A) is incorrect; which of the two types of food is better for consumers is irrelevant to why the chains are offering the items in the first place.

(B) offers no alternative explanation, because the new items were not intended to replace other items completely, but merely to show that not all fast food is junk food.

(C) is irrelevant; people who will never eat at these chains regardless of what they offer are not the cause of any change in menu offerings.

(E) provides some evidence that chains have made other menu changes because of the perception of unhealthiness, so it certainly doesn't weaken the argument that this perception wasn't the reason for the new menu items.

TAKEAWAY: To weaken a causal argument, look for evidence of another cause.

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