Addictions Specialist here (Actually educated, working on Grad School in a related field):
Obesity is due to food addiction.
It follows the same criteria as other addictions.
Most people can drink socially, but others become alcoholics.
Most people could/can do drugs recreationally but others become addicts.
Most people can have sex normally while others need to compulsively (hookers every week).
Most people can gamble for fun while others lose their life's savings.
There are a large number of people who can eat normally while there are others who eat themselves into obesity.
Everyone of the addictive behaviors I just mentioned has their respective 12-Step programs and it is socially acceptable to shun alcoholics, drug addicts, sex addicts, and gambling addicts.
BUT WOE IS HE WHO TRIES TO USE THIS LOGIC ON A FOOD ADDICT.
It's fucking awful. The fat-acceptance movement is a suicidal path that will cause our life expectancy as a society to drop dramatically. I really don't know what to do when I get into the field because for obese people, losing weight has a tremendously positive affect on their health issues.
It is an epidemic and I would say easily on par with the current heroin epidemic issues. I just see so many obese and morbidly obese people in my every day life in school, work, church, etc. and feel like its a losing battle. I was at a BMI of 30 last November and felt god awful. Worked down to a 27.5 and am upping my gym workouts from 2-3 up to 5 no fucking excuses. I;m 6ft 1 208 pounds and just cannot fathom how people let themselves go over 250. Once I hit 220 I realized I had an issue and made life changes accordingly.
It is not easy, but the alternative is death.