The 90 day diet secret is mainly based on the principle called food separation. While you are on such a diet, or a regime, you can actually consume all the needed nutrients for your body, such as meat, carbs, sweets, dairy products, fruits, vegetables, fats, as well as pasta. Practically, as you can see, you can eat anything. The only thing you should pay attention to is how to consume them. You should follow a strict diet plan and keep the rules in terms of how to consume them. You should follow a strict diet plan and keep the rules in terms of how to consume the food as a whole.