How about this?
Food is heated when it absorbs energy from the microwave's passing through it.
Fat, sugar, and especially water absorb energy faster than other food substances. Therefore when we zap or "nuke" BBQ pork [which has a lot of fat, and hopefully moisture, plus some sugars] we get pockets of un-even heat. The fat will liquify, the water will vaporize, the sugars will caramalize or burn. If the product is heated in a covered container, we will get steam, and the old-steam-table smell and taste can develop. The taste and texture of the meat will be changed, not for the better.
We can work around most of this, by heating the meat in a microwave at low heat ranges. I have had good results heating pulled pork, and brisket, and ribs, by running the oven at 20 to 30 percent power max, and using short runs of time [a minute or two, depending on quanity of meat], repeating till meat is heated.
I agree with Neil about duplicating what got you there in the first place, and using low heat percentages and short time bursts is a way to try to duplicate low and slow in the microwave.
Not gospel by any means, just my experiance and opinion:smile:
