Oh I know what you mean. I had a friend who was HUGE and always was eating (and horrible, fatty foods too). She never seemed to be able to change or stick to any of the diets she tried. It became clear that food is just as much an addiction as anything else. She also smoked 2 packs of ciggs a day at a whopping 360lbs. I tried to help her, but it never worked. She had the deck stacked against her as far as life circumstances go, but I really did and still do at time worry for her. Shes a great person, but with her weight being what it is, I dont see her not getting serious health issues in the near future. We had to part ways when I got sober because she wasn't supportive.
You could find empty fast food bags and cartons in her backseat, much like you could find empty bottles under my bed. The parallels between the two addictions are pretty shocking. I dont think people understand obesity and overeating are big addictions too. The worst thing is, their addiction is visible to everyone because of their size. It cant be easy.