Carbohydrate Requirements

Carbohydrates are not essential nutrients, because the carbon skeletons of most amino acids can be converted into glucose . However, the absence of dietary carbohydrate leads to ketogenesis  and degradation of body protein whose constituent amino acids provide carbon skeletons for gluconeogenesis . The RDA for carbohydrate is set at 130 g/day for adults and children, based on the amount of glucose used by carbohydrate-dependent tissues, such as the brain and erythrocytes.
However, this level of intake is usually exceeded. Adults should consume 45%–65% of their total calories from carbohydrates. It is now recommended that added sugars represent no more than 10% of total energy intake because of concerns that they may displace nutrient-rich foods from the diet. [Note: Added sugars are associated with increased body weight and type 2 diabetes.]