I have had craving for marmite too.
Mayo, as long as it says pasturised on the label then it's ok, its the home made kind that contains Raw egg that you need to avoid. Most shop bought jars are fine, but just check label first. OOOh also really fancing Philedelphia cheese, and thought I couldnt have it as it was soft cheese but midwife says you can as it is also pasturised ! woo hoo. find rice cakes with phiily on help morning sickness too.