Many boxed cereals are high in refined grains and added sugars that can spike blood glucose in people with type 2 diabetes. Ajaykumar D. Rao, MD, MMSc, FACP, Chief of the Section of Endocrinology, Diabetes and Metabolism at the Lewis Katz School of Medicine at Temple University, recommended to Everyday Health that patients aim for cereals with no added sugars, at least 5 grams of fiber, and at least 5 grams of protein per serving.