Complex and Fibrous are the same...you probably meant Simple or Complex.
They both have 4 calories/gram. Simple Carbs have very little essential Vitamins and minerals. Ex. includes table sugar, fruit juuice, milk , yogurt, honey, molasses, maple syrup and brown sugar. They are your best choice if you need to quickly replenish your body...in cases of hypoglycemia (for Diabetics) or skipping meals and you feel like you are about to pass out, then your quick fix is simple carb or simple sugar.
Complex Carb or Fibrous Carb - Takes longer to digest and are packed with fiber, vitamins and minerals. Ex. includes vegetables, whole grain breads, oatmeal, legumes, brown rice, white pasta and the likes.
We all need carbs during strenuous activities as we burn our energy, otherwise in a heavy workout, we burn calories, then fats, once you max em' out...you'll end up using your protein which is intended for tissue repair and rebuilding.
Have fun shapin' but save the protein for rebuildin'...
"The doctor of the future will give no medicine, but will interest his patients in the care of human frame, and in the cause and prevention of disease." - T. A. Edison
Ciao,