Many people appear to believe that beef is soy-free. However, this is not the case. Beef contains significant levels of soy protein.  In fact, a 3-ounce serving of beef contains about 10 grams of soy protein. This is more than most plant-based proteins. So, if you are looking for a soy-free source of protein, beef is not a good option.  There are plenty of other sources of soy-free protein available, such as poultry, fish, eggs, and dairy products.  If you are looking for a high-quality protein source, these are all better options than beef.