Experts are warning parents against putting their children on low-fat diets even if they are worried about their offspring's weight.
A US team, led by John Kostyak from Pennsylvania State University, found that fat has an important role to play in helping youngsters develop.
The message comes after pregnant women were warned by a different study that increasing their intake of fatty foods can put their child at risk of obesity.
The latest research, published in the Nutrition Journal, says fat should be included as part of a healthy diet as children burn more body fat than adults for each calorie used up.
The researchers found that the total amount of fat burned by children does not differ greatly to that burned by adults. However, children were found to burn considerably more fat relative to the amount of energy they use.
Tam Fry, board member of the National Obesity Forum and chairman of the Child Growth Foundation, said: "I think this research is absolutely right.
"Young children need more fat and energy for the whole purpose of growing up and living. Therefore to give them low-fat and sugar-free products is a bad idea.
"Fad diets are not appropriate for young children. Diets, period, are not good for them. I would say to parents that a certain amount of fat is a good thing, but don't overdo it."