Figure 2.

Types of processing and structure of grains, sugars, and starches. A major research and policy gap is the absence of one accepted taxonomy to define whole grains or carbohydrate quality that incorporates their various characteristics that can influence car-diometabolic health, including extent of processing, food structure, dietary fiber content, content of bran and germ, and glycemic response to ingestion. This Figure presents a proposed taxonomy to integrate these various characteristics. Types of foods with evidence for cardiometabolic benefits are shaded green, and those with evidence for adverse cardiometabolic effects are shaded red. Intact and minimally processed whole grains (darker green; ie, greater benefits) may plausibly have greater benefits than milled whole grains (lighter green; ie, lesser benefits) because of intact food structure and lower glycemic response; refined sugars in liquid form (darkest red, ie, greatest harms) may have greater adverse effects than refined grains, starches, and sugars (lighter red; ie, lesser harms) because of particularly unfavorable effects on satiety and weight gain. † Both simple and complex refined carbohydrates induce similarly high glycemic responses following ingestion and, in amounts typically consumed in Western diets, induce de novo lipogenesis in the liver, ie, the conversion of carbohydrates to fat. Compared to glucose, fructose produces smaller blood glycemic responses but more strongly stimulates de novo lipogenesis, Animal-experimental and limited human studies suggest that fructose, which represents about half of all sugars in refined sugars such as either high frucose corn syrup or sucrose (eg, cane sugar, beet sugar), may have additional adverse effects on hepatic steatosis and insulin resistance. Corn provides reasonable fiber and modestly lower glycemic responses than many types of potatoes. Yams and sweet potatoes are not included herein because of higher nutrient contents and lower glycemic responses to ingestion.