I lost 60 lbs on the Atkins diet. The REAL Atkins diet, not the one people who don't read the book claim to be on,eating bacon and grease all day. I ate steak and chicken, and after a couple weeks I introduced green leafy veggies into the mix.
I have problems with carbs, always have. If I eat a slice of pizza I'm going to sleep in a half hour. If I ate the same number of calories of brown rice and chicken, or at the same amount of pizza and ice cream, my body reacts drastically differently.
People who say it's simply about counting calories are dead wrong. There is no way you'll maintain the same shape by eating 2500 calories of doritos, soda, and Pizza as opposed to eating 2500 calories of chicken, brown rice, and vegetables. Same number of calories, but you'll look like a slug on the soda and doritos, while you'll be more muscular and lean on the chicken and veggies.