Make a rule for yourself for just a few days. The rule would be that if you didn't plan to eat it, it's just not gonna go down. Explain that to whoever cooks for you. Remember, it's just for a few days. No surprises. See how that goes.
What will happen is - you won't be impulsively dining out with friends. And eventually, if this becomes a habit, you will dine out but review the menu ahead of time and decide on something that looks good and least-caloric from the menu, or else you'll have to find another place to dine.
People were dieting successfully for years and years without having access to modern tools like the Internet and online menus. This means life has gotten easier for dieters, not harder. So, use those tools, just like you use fitday.