I follow a home version of Jenny Craig, so many fruits and veggies, protein, dairy, etc; 3 meals and 3 snacks. Basically a balanced, low-fat diet.
Oh, gosh, I've been doing this a while. Probably about 2 years. No, not a quick loser! There was a period of several months when I maintained (after I got back from a vacation, I lost my drive!).
It really has been a lifestyle change for me rather than a diet, that's why I always say eating program.