Steak is graded by its quality. Choice steak is a common grade, easily available at most supermarkets. Other common cuts include prime or select. The younger the beef and the more marbled the steak, the higher the grade.
The amount of fat trimmed and the cut of steak affect the caloric content of 8 oz. of steak. The more fat trimmed, the lower the calories, for example.
Eight ounces of Porterhouse choice steak has 585 calories, if the fat is trimmed to 1/8 of an inch. Top loin, choice grade, similarly trimmed, has 526 calories in 8 oz. Beef chuck, trimmed to 1/4 inch of fat, has 617 calories in 8 oz.
While you get a significant serving of protein with any cut of steak, you also get a significant amount of fat. If you are watching your caloric or fat intake, select leaner meat options. Round steak, eye of round roast and top sirloin are all graded as extra lean by the USDA due to their lower fat and cholesterol content.