The quantity of vegetables that constitutes an official serving varies, but, as a rule of thumb, a serving of vegetables ranges between a half cup and a cup. Small differences depend on the type of vegetable and whether it is served raw or cooked.
Nutritionists advise that plates should be about half-filled with vegetables at meals; this reduces calorie intake as well as provides quality nutrients. For cooked carrots, broccoli, bell peppers, green beans or carrots, some authorities allow one cup per serving, but the American Heart Association and the Food Pyramid call a half cup a serving. One medium white potato is one serving, compared with a half cup of mashed sweet potato. All sources allow for larger servings of raw leafy greens, such as mesclun and lettuces; one serving of these can be as much as two cups. Overall, a 2,000-calorie daily diet should contain about 2-1/2 cups of vegetables, ideally ones with healthy, vibrant colors.