Naturally sweet, carrots make an ideal high-fiber, low-calorie snack food. Interestingly, cooking actually increases carrots' nutritional value, becuase it breaks down the tough cellular walls that encase the beta carotene.
To properly absorb beta carotene, the body needs a small amount of fat, because carotenoids are fat, not water soluble. Adding a pat of butter or margarine to cooked carrots ensures that the body will fully utilize this nutrient.
Source: Foods that Harm, Foods that Heal, Reader's Digest