A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm.
As part of a general healthy diet, consumption of whole grains is associated with lower risk of several diseases. Whole grains are a source of carbohydrates, multiple nutrients and dietary fiber.
Rolled oats are a type of lightly processed whole-grain food. They are made from oat groats that have been dehusked and steamed, before being rolled into flat flakes under heavy rollers and then stabilized by being lightly toasted.
Thick-rolled oats, or old-fashioned oats, usually remain unbroken during processing. Rolled whole oats, without further processing, can be cooked into a porridge and eaten as oatmeal; when the oats are rolled thinner and steam-cooked more in the factory, these thin-rolled oats often become fragmented but they will later absorb water much more easily and cook faster into a porridge; when processed this way are sometimes marketed as "quick" or "instant" oats.
Brown rice is a whole grain rice with only the inedible outer hull removed. This kind of rice sheds its outer hull or husk but the bran and germ layer remain on, constituting the brown or tan colour of rice. White rice is the same grain without the hull, the bran layer, and the cereal germ. Red rice, gold rice, and black rice (also called purple rice) are all whole rice with differently pigmented outer layers.
Dietary fiber, fibre, or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition and can be grouped generally by their solubility, viscosity and fermentability which affect how fibers are processed in the body. Dietary fiber has two main subtypes: soluble fiber and insoluble fiber which are components of plant-based foods such as legumes, whole grains, cereals, vegetables, fruits, and nuts or seeds. A diet high in regular fiber consumption is generally associated with supporting health and lowering the risk of several diseases. Dietary fiber consists of non-starch polysaccharides and other plant components such as cellulose, resistant starch, resistant dextrins, inulins, lignins, chitins, pectins, beta-glucans, and oligosaccharides.
Food sources of dietary fiber have traditionally been divided according to whether they provide soluble or insoluble fiber. Plant foods contain both types of fiber in varying amounts according to the fiber characteristics of viscosity and fermentability. Advantages of consuming fiber depend upon which type is consumed. Bulking fibers – such as cellulose and hemicellulose (including psyllium) – absorb and hold water, promoting bowel movement regularity. Viscous fibers – such as beta-glucan and psyllium – thicken the fecal mass. Fermentable fibers – such as resistant starch, xanthan gum, and inulin – feed the bacteria and microbiota of the large intestine and are metabolized to yield short-chain fatty acids, which have diverse roles in gastrointestinal health.
Bran, also known as miller's bran, is the component of a cereal grain consisting of the hard layers – the combined aleurone and pericarp – surrounding the endosperm. Corn (maize) bran also includes the pedicel (tip cap). Along with the germ, it is an integral part of whole grains, and is often produced as a byproduct of milling in the production of refined grains. Bran is highly nutritious, but is difficult to digest due to its high fiber content; its high fat content also reduces its shelf life as the oils/fats are prone to becoming rancid. As such, it is typically removed from whole grain during the refining process – e.g. in processing wheat grain into white flour, or refining brown rice into white rice.
Bran is present in cereal grain, including rice, corn (maize), wheat, oats, barley, rye, and millet. Bran is not the same as chaff, which is a coarser, scaly material surrounding the grain and is indigestible by humans.
Steel-cut oats (US), also called pinhead oats, coarse oatmeal (UK), or Irish oatmeal, are groats (the inner kernel with the inedible hull removed) of whole oats which have been chopped into two or three pinhead-sized pieces (hence the names; "steel-cut" comes from the steel blades). The pieces can then be sold, or processed further to make rolled oat flakes, of smaller size than flakes of whole groats. Steel-cutting produces oatmeal with a chewier and coarser texture than other processes.
Steel-cut oats, and other types, are traditionally used to make porridge. They take longer to cook than instant, ground, or rolled oats, typically 15–30 minutes for porridge (or about half this time if pre-soaked). Steel-cut oats are described as being nuttier and chewier than other types of oats. They can be used to make oatcakes, blended uncooked in smoothies, and used for other culinary purposes.
A plant-based diet is a diet consisting mostly or entirely of plant-based foods. It encompasses a wide range of dietary patterns that contain low amounts of animal products and high amounts of fiber-rich plant products such as vegetables, fruits, whole grains, legumes, nuts, seeds, herbs and spices. Plant-based diets may also be vegan or vegetarian, but do not have to be, as they are defined in terms of high frequency of plants and low frequency of animal food consumption.
The Western pattern diet is a modern dietary pattern originating in the industrialized West which is generally characterized by high intakes of pre-packaged foods, refined grains, red and processed meat, high-sugar drinks, candy and sweets, fried foods, high-fat dairy products (such as butter), eggs, potato products, and corn products (including high-fructose corn syrup). Conversely, there are generally low intakes of fruits, vegetables, whole grains, fish, nuts, and seeds. The nature of production also affects the nutrient profile, as in the example of industrially produced animal products versus pasture-raised animal products. Artificial dyes like Red 40 are also prioritized over natural ones.
Dietary pattern analysis focuses on overall diets (such as the Mediterranean diet) rather than individual foods or nutrients. Compared to a so-called "prudent pattern diet", which has higher proportions of "fruit, vegetables, whole grains, and poultry", the Western pattern diet is associated with higher risks of cardiovascular disease and obesity.