It's not just what you eat, but how much you eat that affects your weight-loss efforts. Eating too much of any food — even food that is good for you — adds extra calories. As food is served and sold in increasingly larger portions, it becomes even more important to keep portion sizes in check.
When you first start out on a weight management program, it helps to weigh or measure foods to become familiar with what a reasonable portion size looks like. This can be done with a set of measuring cups and spoons or a kitchen scale. After a short while, you'll be able to visually estimate portions without weighing or measuring. However, every now and then, it's a good idea to pull out the measuring utensils or kitchen scale to make sure your estimates are still on track.