A bowl of children's breakfast cereal adds up to around 10 pounds of sugar a year, a research by Environmental Working Group shows.

Researchers examined more than 1,500 cereals, including 181 marketed to children. They re-examined 84 cereals that were studied in a similar report in 2011 and found that the sugar level in those cereals were 29 percent on average.

The study found that few of the 181 cereals marketed to children was free of added sugars. According to the EWG, on an average, children's cereals have more than 40 percent extra sugars than adult cereals.

Of  these 181 cereals, just 10 met EWG's criteria for low sugar. Among these were Kellogg's Rice Krispies, General Mills Cheerios, Post 123 Sesame Street (C is for Cereal) and Kellogg's Corn Flakes.

"When you exclude obviously sugar-heavy foods like candy, cookies, ice cream, soft and fruit drinks, breakfast cereals are the single greatest source of added sugars in the diets of children under the age of eight," nutritionist and EWG consultant Dawn Undurraga, co-author of the organization's new report, 'Children's Cereals: Sugar by the Pound,' said in a press release.

"Cereals that pack in as much sugar as junk food should not be considered part of a healthy breakfast or diet. Kids already eat two to three times the amount of sugar experts recommend."

The study results showed that Kellogg Co.'s Honey Smacks has the highest sugar content with 56 percent sugar by weight.

According to a Kellogg official, the company reduced sugar content in its top-selling kids' cereals by 20 percent to 30 percent over time. The company stated that the EWG report ignored the benefits provided by a cereal breakfast, including pre-sweetened cereals.

"When you consider what constitutes a good breakfast, cereal and fat free milk pack a powerful nutritional punch, lower in fat and calories than many other breakfast choices, and including many nutrients that people might otherwise miss," said company spokeswoman Kris Charles, reports Reuters.