Carbohydrates are made from: carbon, hydrogen and oxygen and are, essentially, sources of energy that the body breaks down.
Preparing hearty meals that are made from whole grains and complex carbohydrates will help you lose weight.

Refining is where nutrients and water has been removed to increase the shelf life of some foods: white bread, white rice, biscuits, to name a few. Whole grains are foods that have had little or no processing, making them undoubtedly healthier and in my opinion, a whole lot tastier.