[amwelles]

A well-balanced diet will certainly make you healthier and feel better! If you are eating more energy than you're expending, you will gain weight. If you are eating less energy than you're expending, you will lose weight. This is well-researched.

I think, from my experience and from the experiences I've read of people who have lost weight and kept it off, the key is finding a sustainable diet. One that your future, goal-weight self can be trusted to follow even after you're done losing the weight. People tend to get to that point and then go back to eating like they did when they were overweight, which reverses all the hard work they did.