Firstly, how do you know there were no fat people in concentration camps? Where is your evidence for this?

Secondly, I'm certain that in extreme situations where people are starved for years, their body shape remains the same, just with a lot less fat. So my point that people cannot change their fundamental body shape is still correct.

Thirdly, it seems you are desperate for a reason to justify your cruelty towards people who do not conform to your body standards. My guess is that the hatred you direct outwards is hatred you feel for yourself. I hope you find peace.