Microwaving food saves plenty of time, but in the case of one veggie, microwave cooking is zapping elements believed to protect against cancer. A study in Spain compared antioxidant levels left in broccoli after it was cooked by steaming, boiling, or microwaving.
Broccoli that was microwave-cooked with water lost nearly all of its three major antioxidants. By comparison, steamed broccoli lost less than 12% of the same antioxidants.