I can see why you think as you do 4getmenot, but I think we have to take a step back and look at the circusmances.
This man's psychological problems have obviously manifested themselves into a form of self-loathing which has allowed him to gorge himself into his current physical state.
Of course, this doesn't happen over night, but it is surly easy to slip into this dreadful cycle of physical self-inflicted abuse condoned by a partner who fails to acknowledge what is happening in front of her eyes.
If any addict could simply say "I'm getting a big ill / fat / wasted / dead ... it really is time I stopped", that would be the end of any additcttion over night, but of course, it simply doesn't work like that.
Does it?