i read the pizza diet and had some difficulty with the concept.  it would
seem to me that only by feeding consistent amounts for a period
of time and seeing the results would we know whether there is
improvement in the performance from the diet.  what you suggest
sounds like - at least to me - that the horse may like it but 
you would never have a clue as to what gave the best results.
even with human athletes - i suspect the ones that compete seriously
have pretty specific diets that they follow.
regards,
mike maul
mmaul@micro.ti.com
houston, tx