Most cuts of lamb are lean and low in calories. Each 3-ounce cooked shank is between 150 and 185 calories. By trimming away as much fat as possible, you’ll be getting closer to the lower end of that range. If you leave some visible fat behind though, you’ll probably get closer to the higher end.
Lamb does not contain any carbohydrates, so all of the calories come from fat and protein. Anywhere from one-third up to roughly half of the calories come from fat, depending on the leanness of your shank. Each 3-ounce shank contains 6 to 10 grams of fat, or around 55 to 90 calories from fat. The remaining half to two-thirds of the calories are from protein. You’ll get 23 to 24 grams of protein in a 3-ounce lamb shank, amounting to over 90 of the calories.