Trimming excess fat off a roast helps cut calories. But you’ll want to leave some fat in place to flavor and moisten the roast. In this video, you’ll learn how to trim and tie pork, beef, and lamb roasts. All you’ll need is a sharp chef’s knife. You’ll learn why it’s best to chill the roast first before trimming and how to differentiate between thin veins of marbling fat, which add flavor as the roast cooks, and larger strips of fat, which can be removed without sacrificing too much flavor. Then you’ll see a terrific method for tying up boned or butterflied roasts with twine or butcher’s string, creating a series of simple loops and ties.