The AMDR for carbohydrate intake recommended by the FNB:IOM in adults and children is 45–65% of dietary energy intake (FNB:IOM 2002). The intakes were based on the IOM interpretation that there is an increased risk for CHD at high carbohydrate intakes (>65%) and increased risk of obesity with low carbohydrate, high fat intakes (<45%).

a prudent upper level may therefore be 25% energy from protein

Considering all the above, a lower intake limit of 20% energy as fat seems prudent.