Carbohydrates are energy-rich foods that keep you full, and include rice and bread for example. You should base your meals on these and choose wholegrain options where possible as they contain more fibre and nutrients than white or refined starchy foods.
You can gradually introduce more fibre. Changing your diet too drastically, too quickly can cause stomach upsets and make it harder to keep up new good habits. You can gradually introduce fibre by leaving the skin on your fruit and veg, adding beans to curries or mixing bran cereal into your usual cornflakes: the possibilities are many.