I have a couple of friends at work who were into both the Blood type diet and the Aryuveda(dosha) bodytype diets. I thing they've both given up on them.
The Blood Type diet is basically psuedo-scientific BS based on the notion that humans developed the ABO blood types as a result of exposure to different foods. O = hunter gathers, plenty of meat. A = farmers, grains and what not. B = nomads, dairy.
The Dosha is a body type in aryuvedic (traditional indian) medicine, the ones who prescribe heavy metals to Balance your energy. Its alot like the notion of QI but there are 3 different types instead of two. Based on your shape, you apparently have differing amounts of the 3 energies and different foods bring them into balance. Prescientific magic instead of psuedo-science.
http://www.whatsyourdosha.com/http://en.wikipedia.org/wiki/Blood_type_diet