Please Don’t Lie To Restaurant Workers About Your Allergies.
Lifehacker published this article today, How I Lost 100 Pounds, wherein the author says,

This diet means that when I go out to eat (which I do regularly), I can have a steak without feeling guilty. I tell people that I’m allergic to sugar and flour, which gives me a reasonable excuse for being the pain in the ass guy who has to ask the waiter about the ingredients in every dish on the menu. I’d encourage you to tell similar lies if they help you stick to a diet.
For the love of whatever it is you hold holy, please don’t do this.
- We know you’re lying. It shows in your beady little eyes.
- Even if we don’t know you’re lying, we assume you are because we catch so many other people lying to us about this.
There’s no need to lie to us. Just, FFS, tell us you’re on a special diet because you’re trying to lose weight, and if you do feel bad about being a pain in the ass, apologize for being a pain in the ass, and maybe leave us a few extra bucks on the tip.
Otherwise, as a former server, I promise you, we’ll half-ass your requests and lie to you about things in your food, because you’re just another one of those douches who can’t tell us the truth. Not only have I seen this done ten thousand times, I’ve done it myself, because after you’ve been blatantly lied to often enough, you just flat stop caring.
TL;DR: Bad Lifehacker. Bad! No cookie.