VeritasKarishma mam GMATNinja sir Kindly explain how to choose between Options D and Option E

(D) is much cleaner and clearer. After 'because' it uses a clause. The parallelism is clear "more because their bodies burn ... than because they eat ..."

(E) uses the awkward construction "their doing...".
"their bodies burning" - bodies is the noun and burning modifies it.
but "their eating" - eating is a gerund.
The parallelism is not very clean.
_________________

I'm clearly late to the party here, but I'll add my two cents, just in case it helps anybody.

Whenever I see the construction BECAUSE + OF, my expectation is that the next word is going to be a noun that caused something. For example:

Tim refused to take his children to school because of the rain.

What was the cause of Tim's refusal to take his children to school? The rain. This construction is fine. Not a great reason to deny your kids an education, but logical enough.

However, if I see "BECAUSE" without "of," my expectation is that a full clause will follow, and the clause's action is what caused something:

Tim refused to take his children to school because he preferred to sleep late and eat chocolate doughnuts in bed.

Why did Tim to refuse to take his kids to school? Because he preferred to do something else, namely to sleep late and eat chocolate doughnuts in bed. (Mmm... doughnuts. ) This time an entire clause functions as the cause of Tim's terrible parenting. This is also okay.

The problem is when we see BECAUSE + OF and the writer tries to communicate that the cause isn't simply the ensuing noun, but rather an implied action. For example:

Tim refused to take his kids to school because of chocolate doughnuts having been eaten in bed by Tim.

When I see "BECAUSE + OF," my expectation is that the noun that follows is the cause of Tim's refusal. But chocolate doughnuts themselves didn't cause Tim to refuse to take his kids to school. If I read the sentence a few times, I can probably figure out what the writer meant to convey, but because my default interpretation is illogical, this construction is problematic.

We get a similar problem in (E):


At first glance, the BECAUSE + OF construction makes it seems as though the bodies are themselves the cause. But that doesn't make sense. The people aren't obese because of their bodies. They're obese because their bodies do something. Again, I can probably figure out what the writer means if I reread the sentence a few times, but this version is confusing at best.

Contrast this with (D):


Now, when I see BECAUSE without the preposition, my expectation is that the entire ensuing clause is the cause of the obesity. This makes perfect sense -- the people in the study are obese because their bodies burn calories too slowly.

Because (D) is clearer and more logical than (E), (D) is our winner.

I hope that helps!
_________________