A character taken from a DnD rp session (that's proper RPG pplz!)

Xerxes is a half Drow, half Gith'Zerai created by the Illithids as an experiment... and was continually starved becoming greatly emmaciated (even by Gith standards).

After being rescued by Grakt (the man can do no wrong), he was able to eat again, as much as he wanted. So he returned to his normal weight.
But as he continued to overindulge he started gaining more weight, unlike full-blooded Gith that are genetically unable too.

So... there you have it.