Of course not. Whenever you start thinking "everyone," assume you need to think it through more carefully. Some people are fat because they eat too much but if they're really happy that way, it's not healthy but they're not ill. No different than someone who sky dives -- not very healthy, but they like it so they do it anyway. Stress and sadness aren't examples of disease. They are facts of life for everyone, and people react differently to them. Some are fat because they take medication that makes them that way. Some are genetically predisposed to it and have to work harder than they want to in order to overcome it. Some just like to eat the wrong foods more than they like to be thin. Life's variety, not the same for everyone.
I was over weight and lost 70 lbs 35 years ago. My problem was self discipline. After I finally convinced myself that I could change, I lost the weight and have kept it off. It was a problem of making myself do it. I gained lots of self confidence once I made myself take control of my weight and my health. Gaining the self discipline helped me in many ways. After taking control of my weight problem and staying in control of it,I felt I could accomplish about any thing I wanted to do...and was pretty much correct...so just make up your mind that you can do it and then do it..hope this helps...claytex