One cause of obesity and related diseases like type-2 diabetes is overconsumption of cereal foods with readily available carbohydrates, resulting in hyperglycaemia and ultimately insulin resistance. A strategy to combat this is to modulate glycaemic response through starchy cereal foods that have low glycaemic index (GI) because their starch is less available to digestion. In cereals, many factors can limit accessibility of amylase to the starch. Of these, intact pieces of endosperm, high levels of oat or barley β-glucan and high amylose starch are probably the most important. Starch accessibility in cereal foods is also greatly affected by processing. Heat-moisture thermal processing at low moisture above glass transition temperature, but below gelatinization temperature is probably the most effective processing technology to reduce starch availability. Formation of starch-lipid complexes also appears promising. Whole grain (milled whole kernel) cereal foods are intrinsically low GI but may have a long-term role in preventing obesity and type 2 diabetes through their phytochemicals, particularly polyphenols. A novel approach is to structure starchy cereal foods to deliver their carbohydrate at the distal end of the gastrointestinal tract to trigger the ileal and colonic brakes feedback systems so as to enhance satiety and hence decrease energy intake.