Finding out the right amount of carbohydrates for you should be a collaborative effort between your healthcare provider, a dietitian or nutritionist, and you. One formula does not apply to all people. but roughly 45 to 66 percent of daily calories should be carbohydrates.
The National Academy of Sciences has published new dietary recommendations: Adults should obtain 45 to 65 percent of their calories from carbohydrates, 20 to 35 percent from fat and 10 to 35 percent from protein.
The best meal plan for you, however, is the one you will be able to stick to.
Sources:
"Dietary Reference Intakes: Recommended Intakes for Individuals, Macronutrients." Dietary Reference Intakes Table - The Complete Set. 2002. Food and Nutrition Board, Institute of Medicine, National Academies. 29 Nov 2006
"Using The Diabetes Food Pyramid." Making Healthy Food Choices. American Diabetes Association. 29 Nov 2006
