I saw on some talk show, that overweight/obese people eat normally in front of people but they privately binge on food when no one is around, especially junk foods. They have a psychological attachment to food and it gives them comfort and even a feeling of love and intimacy. They fill themselves up as much as they can. They dont tell people about it, it is like a seperate life.
I always used to think it was metabolism that determined why some people are fat, but its not, fat people eat secretly.