Before you launch into the diet, you need to get to grips with your body's basic needs so that you don't suffer deficiencies as a result of dieting.
A balanced diet should obtain around 15% of calories from protein, 30-35% from fat and 50-55% from carbs, preferably complex carbs. So there's to be no cutting out fat (oil, butter etc), meat, fish or cereals because you think they're too calorific.
If you want to lose weight, you need to combine low and medium calorie density foods, eat a measured amount of fat, and avoid foods with a high calorie density.
The key is to eat when you're hungry, without restriction. That's why the plan is easy to follow: you just need to learn how to combine healthy, filling, low calorie density foods to your advantage.