A lot of guys in here don't realize how important height is with regards to optimum weight.
^^ and that is at 6% body fat. Now add roughly 15-20lbs for each height and that is what you got fighters in the UFC typically weighting based on their height. The exception is LHW and HW though... Larger frames and height give you more to fill up and you don't sacrifice as much as a shorter guy does who bulks beyond what is effective for his height like Mark Hunt who is practically Obese and 5'10 fighting at HW and having to cut to make 265lbs.....
Hunt also gives up TONS of reach, leverage, and size by fighting significantly taller fighters while he himself is overweight carrying excess fat. It isn't optimum for health, fighting or athleticism.