My boss's boss is coming to town and is taking my team to a fancy sushi lunch. I work in finance in NYC so we are all big sushi snobs. My coworkers will definitely notice if I order anything other than the chef's choice option. I will be about 14 weeks at that point so will probably be at the point that people are starting to suspect that I'm expecting but aren't willing to ask (and I won't be ready to tell). Avoiding the lunch entirely isn't an option. 

Any advice on how to handle this? What excuse can I use for not eating raw fish when everyone already knows I love it? Has anyone tried calling a restaurant ahead of time to order?