You may think you know all there is to know about protein—but you might be surprised...

"Oftentimes, protein is only associated with building muscles, but it has so much more to offer," says Jordan Mazur, M.S., R.D., director of sports nutrition at the University of California, Berkeley. "Protein consumption in our diets is not only critical to building and supporting our lean body mass, or muscle; it’s also important for a number of functions and structures in the human body," he explains. It helps make enzymes and hormones, boosts energy levels, helps your memory stay sharp, helps control mood swings, stabilizes blood sugar levels, and can help you maintain or lose weight by promoting fullness and satiety. "Protein is also the second most abundant substance in the body after water," Mazur says. It's a crucial power source for your body's cells. 

Obviously you associate protein with heavy hitters like steak, chicken, fish, eggs, and dairy. But, Mazur says, there are alternative sources of protein that can add a new range of nutrients and eliminate some of the monotony in your diet. Here are 10.