Ruin is a hefty word.
Maybe next time you go out to eat try eating some veggies that are roasted, steamed, or ****, order a salad. You could always order a meat-dish; ask waiters what it's cooked with and see if you can get them cooked with olive oil.
It also really helps to explain to your girlfriends that you're dieting. Most of the time, they get it. If they don't, just stand your ground and say no. Might hurt their feelings at first if they're really sensitive about sharing food with you, but over time they get used to it.
Are there other foods you can eat? Stock up with foods you can cook and eat that taste good. But I do admit, I have a fatal attraction to almond butter and dairy. Today I had 4 servings of almond butter, and 5 servings of dairy. However, I don't let it get me down; tomorrow I plan to have veggies with every meal, and only one serving of almond butter and dairy. I'm sure my weightloss will be fine; I'm sure yours will be too. Get back on the saddle!
It's also really helpful to write stuff down. This diet is kinda intense at first. Writing it down helps me see what I need to eat more of and what I need to eat less of, and what made me feel more tired during the day, and what foods made me feel energetic and full. Those records are important, don't forget them!