Here is a thorough review of the science in the book, by a credible Nutritional Sciences PhD student (Chris Masterjohn).
His conclusion:
Despite disagreeing with some of the points in Wheat Belly, I think Dr. Davis is essentially correct that modern wheat products are representatives of the type of hubris that is destroying the health of modern humans
and
But I do agree that the processed junk Dr. Davis calls "wheat" should be purged from the diet, that the development of dwarf wheat has taken its toll on us, and that we should steer clear of the packaged foods and meet Dr. Davis for a pow wow in the produce aisle.
On a personal note, I had fatigue issues that were partially cleared up by eliminating wheat, but it wasn't until going fully Paleo (my favorite variant) that my health really improved.