From Mayo Clinic
Struggling with your weight? Check your portion control. You may be confusing portion control and servings. A portion is the amount of food you put on your plate. A serving is a specific amount of food defined by common measurements, such as cups or tablespoons.
For instance, a pancake serving is 4 inches (as shown on the left). But a typical portion you might eat is 6 inches — or 2 servings. Similarly, a serving of milk is 8 ounces, but the portion you pour might be twice that size, like the one on the right. If your portion control is out of control, you may be supersizing your meals and yourself. Use this guide to become a better judge of portion control and serving sizes.