I have been doing this now for 2 1/2 yrs, so I know what foods I have issues with and avoid them for the most part (do a little cheating, maybe once a week now and then).
When I do try something new, try to keep everything else constant so I can evaluate the new food or supplement.
That is the way I approach it, does not mean it is the best method

Tim
Hope is only a post away with KickAS.