Certain lectins in food grains bind to glucosamine in the intestines and
tissues, and cause red blood cells to clump together. The Wai diet is good in
that it is virtually (excepting egg yolk) lectin-free. Lectins are storage
proteins in grains, legumes, nightshades, that protect them against consumption
by predators. Modern grain varieties have been engineered to have high lectin
content to complement pesticide use. The high lectin content in these foods is
strongly linked to arthritic conditions as well as auto-immune disorders. As
lectins are found in the germ of seeds refined grains are pretty much
lectin-free. Avoiding lectin consumption is helpful in avoiding their effects
(obviously). Here's a good introduction to the topic: