Fruits DO NOT mix well with any other food group! Fruits should be eaten alone as a meal on an empty stomach. Fruits (especially tropical ones) have digestive enzymes that help to clean out the residue left over from the food you've eaten the day  before.
Pineapple is a great fat burner and roto-rooter, scrubbing and cleansing its way through your intestinal tract. Papaya helps with digestive health and contains lots of beta carotene, which is great for eye health. Soursop helps the body to fight cancer. The list is endless :)

Fruits travel through the digestive tract very quickly (within an hour) which is why it's so important not to eat them with any other food group. Fruits are made up of 4 groups: Acid fruits, Sub-Acid Fruits, Sweet Fruits & Melons. With Food Combining, you typically NEVER want to mix any of the fruits with any other food group, and each fruit group should be eaten separately from one another. HOWEVER, you can mix fruits that are close in digestion time.