Any of the 'fad' diets. No, carbs aren't evil. Protien isn't evil. You didn't magically lose weight by "not eating carbs". You lost weight because you cut out an entire food group from your diet - you were eating less. Otherwise just known as dieting. Make it easier on yourself and just limit your calorie intake. That's pretty much it.

You can eat pizza and still be dieting. You may be eating 1 slice for an entire meal because it's just a calorie dump, but you can do it.