How to avoid problems with dieting.

When I think or discuss questions of dieting for weight loss, I have a feeling that a lot of information sometimes causes a lot of problems.
Take for example the information that if you are overweight and you lose the weight through diet or exercise, whatever, you will most likely gain it back eventually, plus a little extra. I consider that it is a full nonsense. After reading of such information many people will be getting discouraged. What's the point of trying to lose weight, if you will gain your weight back plus more! For me it sounds like why trying to fight with the disease, if you will die in the end of ends!