In my office I have fake (rubber) foods to show clients appropriate portions. The foods are a little comical and quite unappealing, but I feel they help to get the point across. How much you eat is so important. Any food can fit in a healthy diet but portion control is essential.
You can actually buy a portion plate to reinforce the need for portion control. Here is an example:
Half of your plate should be fruits and vegetables, one-quarter of your plate should be lean protein, and one-quarter of your plate should be whole grains. You can have a full plate of food, but you need to fill your plate with the appropriate combination of fruits, vegetables, whole grains, and protein sources. Many restaurants serve half a plate of high fat meat (6-8 oz) and half a plate of fried potatoes. Eating 12 servings of grains at Olive Garden (3 cups of pasta and 3 breadsticks) is not going to help you achieve your weight loss or weight maintenance goals. Instead try eating a salad first (salad dressing on the side and use sparingly) and limit yourself to 1 cup of pasta, 1 breadstick, and a lean source of protein.
The more food we are presented with, the more we eat. Some people eat out every day at lunch and many times each week for dinner, and the result is weight gain. One test is to ask yourself how you feel after a meal. If you feel stuffed and uncomfortable, then you ate too much. Eating at home and portioning out your plate appropriately can help you maintain a healthy body weight and still eat a whole plate of food!