I saw a meme that I liked a lot (which is saying something): People who say the glass is half full or half empty miss the point; the glass is refillable. I think the same can be said for those who eat a course or meal that is non-Paleo or not in their diet plans. They think that if they eat a slice of pizza or a slice of cake, the whole day is ruined and they might as well just eat whatever they want and start again the next day. Who says you have to wait until the next day?
I have encountered non-Paleo foods at every picnic or BBQ I’ve attended since going Paleo, and instead of avoiding everything, I either limit my portion sizes or just eat a bit and then continue to try to find the best Paleo-friendly choices I can. There’s nothing that says an entire day is going to be ruined because I had some pizza or non-Paleo potato salad.
Changing your lifestyle is playing the long game. You may get short-term gains here and there, but you’re not changing your eating habits for a quick gain and then going back. You’re adopting a whole new way of thinking when it comes to food, and forging a new relationship with the things you eat so you can cut out those things that hurt you and eat only those that nourish you. Every now and then, a rogue item isn’t going to kill you. Only successive courses and meals will derail and sabotage you.
Don’t beat yourself up. Be as good as you can, but give up on eating well for an entire day just because you ate some sausage with sugar and nitrites in them. Avoid the cake and continue eating well. You’ll be just fine.