Ever seen a 'medically fat' tiger or a 'medically fat' owl? No -
This could be due to the fact that any tigers or owls that have a genetic defect would be very unlikely to ever survive in the wild.
I agree that probably 99% of obese pax are that way due to a lifestyle choice, but I would like to hear a qualified medical expert state that there are no genetic or medical conditions that can lead to obesity.
Don't forget that psychological conditions are medically recognised, and some of these can cause over eating through no fault of the person concerned.