All the information you will ever need concerning recommended daily allowances (rda) is found here.
Since I imagine most people won’t check the link… I’ll take the liberty of condensing some of the info for you.
Carbohydrates (the name derives from carbon plus water) are one of three types of nutrients – the other two being protein and fat. Nearly all foods (except for oils/fats) contain a mixture of carbs, protein and fat, but what makes carbs different is that they are easily converted to energy by the body, so they supply most of our energy needs. This doesn’t mean that carbs are more nutritious than fats or protein. Both fat and protein are absolutely vital for good health, and without a balanced diet of carbs, fat and protein, the human body quickly becomes malnourished.
Recommended Daily Allowance for Carbs
According to the Dietary Guidelines for Americans, published 2002, we should eat enough carbohydrates (mainly the complex low glycemic-index type of carbs) to account for 45–65 percent of our daily calories.
What are the Types of Carbohydrate?
Simple and Sugary Carbohydrates
Simple carbohydrates are sugars, like glucose, fructose and lactose. Common sources include table sugar (sucrose), boiled sweets, syrups and honey.
Complex and Starchy Carbohydrates
Complex carbs are either starches, or indigestible dietary fiber. Common sources of starches include, bread, pasta, rice, beans and some vegetables. Common sources of dietary fiber are fruits, vegetables, beans, and the indigestible parts of wholegrains like wheat bran and oatbran.