Hi Elena Plescan,

This question is designed in a "quirky" way - you have to understand what the word "plumper" means to correctly answer it.

The Facts:
-The media portrays an idea of the relentless pursuit of fitness.
-In 2008, the average adult is 11 pounds HEAVIER than the average adult in 1978

The Conclusion:
-The population of the nation (in 2008), on average, is PLUMPER than the population 30 years ago (in 1978).

The Logic:
-We don't have a lot of information to work with - just the relative difference in average weights of the adult population at 2 points in time. The prompt connects the +11 pounds of weight to being "PLUMPER" - meaning that the extra weight makes the 2008 population look fatter/thicker/fuller than the 1978 population. We're likely looking for an answer that either confirms this idea or REMOVES the possibility that the extra 11 pounds has done something other than make the population look plumper.

The only answer that addresses this issue is Answer E. A taller person could (and probably would) be heavier without looking plumper - if this were the case, then the argument wouldn't make sense. The logic has to assume that the 2008 populace isn't significantly taller than the 1978 populace. Answer D focuses on the age of the populace, but we have no information to work with that connects age with "plumpness."

GMAT assassins aren't born, they're made,
Rich