Carbohydrate Intake from Complex and Simple Carbohydrates

Is there a recommendation for what percentage of your carbohydrate intake should be from complex rather than simple carbohydrates?

Why are complex carbohydrates healthier than simple sugars? What are the primary sources of complex carbohydrates? What is the recommendation for our intake of “whole” grains”? Why are they considered so “healthy”? What role do complex carbs play in preventing obesity? How do they contribute to weight management? What prompts the release of energy from storage? How does this fit into our risk for developing type 2 diabetes?