Researchers at the Environmental Working Group said cereals marketed to children with cartoon characters on the box were among the most highly sweetened. Seventy-eight percent of the children's cereals averaged 2 teaspoons per serving.
A typical serving of cereal marketed to children can contain as much sugar as three Chips Ahoy! or two Keebler Fudge Stripe cookies, the analysis said.
On average, 34 percent of the calories in children's cereals came from sugar.
Even though previous research found children ate low-sugar cereals, U.S. supermarkets offer few.
Americans consume, on average, 22 teaspoons of sugar a day, or 16 percent of total calorie intake.
The World Health Organization is proposing a new recommendation that sugar should make up less than 10 percent of total calories per day. However, a reduction to below 5 percent of total daily calories, or 6 teaspoons of sugar per day for an adult, would be even healthier.