Re: "fat" elves. This is an interesting enough tangent, so I'll bite.
It has always been implied if not infrequently mentioned that elves have a perfect metabolism and perfect or near-perfect hygiene. I accept that elfs are essentially universally slender because there has never been - at least as far as Dungeons & Dragons is concerned - a consistent depiction of elfs featuring the odd overweight specimen. At best, an elf may be somewhat muscular in the same way a world-class archer, sprinter or swimmer is muscular.