Chicken isn’t the only lean source of protein. The other white meat has some serious nutritional benefits. According to the U.S. Department of Agriculture, pork is 16 percent leaner than it was more than a decade ago. Three ounces of roasted pork tenderloin has about 120 calories, three grams of fat and nearly 23 grams of protein. It also provides a healthy dose of niacin, thiamin, riboflavin and vitamin B6 , which plays an important role in protein metabolism and immune function.