A diet isn't a short term thing, it's a way of life. Not just for weight loss.
Just eat well, keep away from refined carbs, keep carbs complex, lots of lean protein, some good fats (mono and poly unsaturated, though some sat fat is also actually ok), and you can have a little dairy. Everything in moderation, up the exercise, and eat 3 good meals a day and avoid snacking on refined processed crap like chocolate etc...