Make it a point to plan your restaurant outings ahead of time. You can view or print Nutrition Facts for most restaurants (including fast food) online. Knowing your options ahead of time helps you make smart choices.
You can also access Nutrition Facts on a smart phone when you get caught out spontaneously. I do this often myself. Or just wing it and stick to meat and green veggies - broccoli, salads, green beans, etc.
For fast food, I stick to burgers or grilled chicken sandwiches. They can be messy without the bun, so if you know you're going to "drive thru" you can always carry a Low Carb Tortilla with you in a ziploc bag. Goofy as that sounds, it beats making a mess!
Speaking of carrying things with you, I often keep Low Carb Snacks handy. You never know when you're going to get hungry - or just have a craving! - with nothing but carbs in sight, if anything at all.
Snacks I carry in my bag include Quest Bars, Atkins Bars, string cheese, almonds, pecans and sugar free candy. One of my favorites is snack-size Hershey's Sugar Free Chocolate Caramel Bars. These are a great treat to have on you when you're avoiding other dessert options while out! ;-)
Invited over for dinner? Offer to bring a dish to complement the meal. This will give you at least one item within your control. Eat light and stick to meats & greens if available.
If you're good friends with the person cooking, let them know ahead of time that you're eating low carb or on a diet. You might say "Don't be offended if I eat light. I'm on a diet." Saying this in advance might prompt them to ask you what foods you *can* eat and make sure to include those. It's also a good time to discuss the dish you might bring.
I don't often come right out and say that I'm on a low carb diet, whether to friends or to waitstaff at a restaurant. It invites all sorts of funny looks and misinformed comments. "I'm on a diet" will usually do.
Above all, simply make smart choices. Every bite you take should be a conscious decision!
Lynn Terry, aka @LowCarbTraveler on Twitter