Why do people diet (since it backfires, and often gain more weight)?

Diets in general don't work because they're set up to be a short term solution to a long term problem. If someone can commit to a lifestyle change and stick with it long term, success rates are much higher.

I started "dieting" two years ago and had to cut out junk food, lots of carbs, and sugary foods: After losing 25 lbs, I made a decision not to return to eating these things, although I occasionally eat a piece of cake or some fried food: The interesting thing is that the less I ate of these "bad" foods, the less I craved them, so the long term solution has become easier and easier.

I think most people are looking for a "quick fix" for weight and health problems and need to think about what will lead them to a healthier leaner life.

Not all diets created the same. wrong ones lead to gaining weight again. but considering a diet is a new lifestyle that the person can enjoy, is something different.