I'm not as concerned so much about his weight, more his attitude. In that type of environment after, what, 15 years of living in a post-apocalyptic society, that he would be, I dunno...less of a dandy tenderfoot. Again, if the lights went out just yesterday, yeah, I could understand it. But he and his cohorts have been living in an extremely difficult environment, under threat of attack from rival groups and the militia for a really long time. If he acts like he does at this point in the game, I seriously doubt he would have realistically lasted more than a year.
That was the point of him leaving his wife (a future storyline, to be sure).
Here's the thing.. he's "Google guy", meaning his WHOLE IDENTITY is wrapped up in computers. Without them -- he has no idea what he should/could be doing. Career interest tests (which looking back, were pretty accurate even 20 years ago) would be unavailable (as they're all online nowadays), so he'd have to do trial and error to figure out where he fits. His last gig seemed to be teacher, and one that i think might have come about after trying just about everything else.
It's this new adventure where Aaron is actually finding himself, and who he is.
While there was danger the previous 14 years...i think they had been relatively safe/unchallenged. I doubt he had even been trained to fight...but now he is learning how to kill (for the right reasons), among other strengths he previously didn't need.
He might seem annoying...but i feel like i can relate to his journey (which is clearly not done).