Hi Sue
God protect us from all the aspartame-hating non-AS sufferers who write intellectual responses to posts on this forum!
You write "..to hold all variables except one..the test variable, constant over a prolonged period...in order to deduce a 'scientific' connection between diet and AS or diet and illhealth generally, is well nigh impossible". Isn't that what Ebringer has done in the case of AS? Of course not successfully isolating the single variable would be an explanation of studies which failed to prove the AS-diet link. There are of course people like myself who would swear the connection is so direct it is obvious (like John with his doughnuts, french fries and buns).
Wally
