However, the macronutrient profile of soybeans differs in some important ways from most other legumes. Soybeans are higher in both protein and fat than other beans and are relatively low in carbohydrates. Soybeans derive about 35 to 38 percent of their calories from protein compared to approximately 20 to 30 percent in other legumes.
Soy protein is also of the highest quality.
Under new guidelines adopted by the Food and Drug Administration and the World Health Organization for evaluating protein quality for children and adults, soy protein isolate receives a rating of 1, which is the highest possible score. This means that the quality of soy protein is equal to that of meat and milk proteins. The fat portion of the soybean is used extensively both in the food industry and directly by consumers. Most of the fat in soybeans is unsaturated. Soybeans are one of the few plant sources of omega-3 fatty acids.