I think weight issues are a mixture of psychological issues and addiction. I think there are a lot of comfort eaters out there, poor self esteem, depression, unresolved issues, previous abuse, medical problems, social anxiety. Coupled with the addictive nature of junk food which acts as a comforter. Reducation and Cognitive behaviour therapy is needed. And I agree about gym membership being too expensive!
It's never as simple as just being lazy and greedy. There is always something behind it, even the most cheerful fat man who loves food, there is always an issue in the background.