Oatmeal comes from the oat plant, which is considered the third most important crop in the United States. Oat is grown in all of the continental states, though most of it is used for feeding livestock. Only 5 percent of the oats grown are for human consumption.
The oat plant is similar to wheat as they are both types of annual grass. Oats are believed to have their origins in Asia and Europe. The plants were used heavily in Europe before America was settled and continued when settlers came to America's shores. Several types of oatmeal has developed over the years, including steel-cut, rolled or instant. The differences are in the preparation. Steel-cut oats are chopped, rolled oats are dehulled and flattened and instant are dehulled, flattened and cooked until done.