Bringing your own food on a Hag is a good solution. Some Hagim (like Hanukkah) has no low carb version, and here on this thread we should put our heads together and put together some good recipes. I don't find it hard to do LC at all. Most cafeterias serve meat and veggies, I just skip the rice and couscous. I buy a Shawarma and throw away the pita, at friends houses they usually serve "Pizuhim", nuts, along with the cookies.