Many grains, even those that contain protein, are generally not considered typical sources of protein. Oatmeal is one of the few exceptions, however, oat protein is different from other grain proteins and is considered a comparable quality to many other protein sources. Additionally, oat protein mixes well with other protein sources to promote muscle growth when combined with exercise or fitness activities.

Oatmeal has the highest protein content of all grains. Like other grains, oats contain a protein called propylamine. Unlike other grains, however, oats also contain a protein called globulin, which is thought to be similar in composition to the protein in beans. Oatmeal can be turned into a milk-like substance due to the water solubility of globulin, but cannot be turned into bread without the addition of another grain of flour.

An oat grain without a husk, called a groat, has between 12 and 24 percent protein. This number depends on the type of oats, as there are several different types. One cup of commercially available cooked oatmeal typically contains about 6 grams protein. Oatmeal has several other nutritional benefits, including zinc, iron, vitamin E, magnesium, and soluble and insoluble fiber.

According to the World Health Organization, oat protein is comparable in quality to soy protein. The organization also considers soy protein to be of comparable quality to a protein found in meat, eggs, and milk and puts oat protein at that level of quality by comparison. However, this information refers to the effect of these proteins in the body after consumption, not the protein content of oats, soy, meat, eggs, and milk. In particular, the protein content of meat and eggs is significantly higher than that of oats.

Oatmeal is good for fitness and exercise, whether before or after a workout. Since oats are considered a complex source of carbohydrates and protein, oat protein is often recommended to be mixed with other protein sources, such as whey or soy. This method has proven beneficial for building muscle, speeding up the post-workout recovery phase, and even burning fat. In addition to the protein content, oats also increase glucose levels in the body in the long term, helping to combat fluctuations in insulin levels.

Bodybuilders often add oats and other types of protein to their shakes. A typical oat protein shake may contain oats, nuts such as almonds, protein powders such as milk, whey, or soy, and sugar-free sweeteners or made with non-monosaccharides. This protein blend promotes muscle health and growth.