An important source of 10 essential nutrients, including iron, zinc, B-vitamins, and protein, a 3-oz. serving of lean beef provides about 150 calories, making it one of the most nutrient-dense protein foods around. Animal proteins -- such as lean beef -- are complete, high-quality proteins that contain all of the essential amino acids your body needs. Lean beef is a calorie saver, especially compared to other protein choices. In fact, to get the same amount of protein found in lean beef, you'd have to consume two to three times more calories from plant proteins.
Grass-fed beef has roughly 80% less fat than grain-fed beef, making it a healthier choice. It also has an increased amount of Omega-3 fatty acids, vitamins A and E, and antioxidants that contain conjugated linoleic acid (CLA). CLA’s are believed to enhance muscle growth as well as lower the risk of various diseases including heart disease, diabetes, and cancer.