A serving of whole grains can be considered a half cup of hot cereal such as oatmeal, cooked grain such as rice (including the “pseudograins” amaranth, buckwheat, and quinoa), cooked pasta, or corn kernels; a cup of ready-to-eat (cold) cereal; one tortilla or slice of bread; half a bagel or english muffin; or three cups of popped popcorn.