what's the quickest you've transitioned?

Julie
My 3 week old has mucus, stringy, runny poop and I've eliminated dairy and soy but it is in almost all processed food so it's very hard to eliminate 100%. I am following the guidelines to transition to formula (substitute 1 feeding for 3 days and then 2 feedings for 3 days etc) but he's so miserable I don't know if I should do it quicker.