How Do You Make Spaghetti for 50 People? offers a spaghetti recipe that serves between 10 and 14 people. To make spaghetti for 50 people, you must multiply the serving size by 5. In this case, required ingredients for a group of 50 include 10 pounds of Italian sausage with the casings removed, five small chopped onions, 15 to 20 minced garlic cloves, five 28-ounce cans of diced tomatoes and 10 6-ounce cans of tomato paste.