The guidelines recommend that cereals have no more than 26 percent added sugar by package weight.
Here are three of the most sugary, according to the Environmental Working Group.
Kellogg's Froot Loops Marshmallow has more than 48 percent sugar, Quaker Oats Cap'n Crunch "oops!" All Berries has almost 47 percent and Quaker Oats Cap'n Crunch Original contains 44 percent sugar.
Some major-brand cereals that got a good rating include Kellogg's Mini-Wheats, General Mills Cheerios and General Mills Kix.
