Your daily need for carbs is directly related to the amount of fuel you burn in your muscles. If you are young and physically active you can burn more carbohydrates for fuel. If you are an adult with little daily physical activity you need little carbohydrates for fuel. This can be called as your carbohydrate tolerance. If you exceed your carb tolerance in your diet than the excess carbohydrates are converted into fat and stored in your
If carbohydrates can be bad for you, should you actually eat none? That is a bit extreme since plants and fruits are very important for a balanced diet due to their high content of Vitamins, Minerals, fibre and other goodies.