Many of the goodies for diabetics in vegies can be lost in microwaving,
unless cooking water is also consumed:

NY Times
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  October 21, 2003
 
     VITAL SIGNS

  Nutrition: Cooking Broccoli, Out of the Box
 
     By JOHN O'NEIL

     Broccoli is prized as a healthy food in part because it contains high
     levels of chemicals believed to protect against heart disease and some
     kinds of cancer. Now a new study from Spain suggests that health
     lovers hoping to get those benefits keep their broccoli away from the
     microwave.

     The study, published in the November issue of The Journal of the
     Science of Food and Agriculture, found that broccoli cooked by
     microwave lost 74 percent to 97 percent of its antioxidant compounds,
     which are believed to be healthful. The researchers, from the
     University of Murcia at Espinardo, found by contrast that broccoli
     cooked by steaming lost less than 10 percent of the same chemicals.

     The study's lead researcher, Dr. Cristina Garcia-Viguera, wrote that
     nutrients were leached out of the broccoli into its cooking water
     during microwaving. Because there is less contact between water and
     vegetable during steaming, fewer chemicals are lost, she said.

     Marianne Turow, an associate professor of nutrition and food safety at
     the Culinary Institute of America, said that she had no reason to
     doubt the validity of the study, but that she would not change her
     regular practices to keep her broccoli or other vegetables out of
     microwaves entirely.

     She said it was possible to microwave vegetables with less water than
     the researchers used, and sometimes frozen vegetables can be
     microwaved without adding any water. "Unless you like raw potatoes,"
     she said, "you've got to cook usually, so there will be some loss."
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