For example, 1 cup is about the size of a woman's fist, 3 – 4 oz is about the size of a deck of cards and 1/2 cup is about the size of a computer mouse. Try ordering a side dish or appetizer for a smaller portion of food.Try to visualize how much you should eat and push away the extra food. Ask for a box to take home the leftovers.[10] Like at home, always leave food on your plate when you go out to eat. You can also have the server box half of your meal up before it arrives.