I've been given a diet by the dieticians at my hospital, but to be honest it's beyond useless! In general they smugly sit there and tell me that they find some TMAU patients so funny because "they think they can't eat anything" and then hand over a diet plan that is full of completely unsuitable things!
The rule is to pick out the low choline foods and then eliminate anything that contains torula yeast or soy lecithin. High carnitine foods are also best avoided, as carnitine is also a precursor to TMA. Again you can use the calculator at http://nutritiondata.self.com
Observing these rules has lead me to all kinds of alternatives: rice milk instead of dairy milk, using low-fat coconut milk as a sauce base for Jamaican-style stews, rice flour instead of wheat flour for white sauces and baking, egg white omelettes etc, etc. It's all about being creative and knowing the limits of your ingredients.