This is such a dangerous attitude.
"Oh, I had too much cream in my coffee this morning! I have totally screwed up. I might as well have chocolate cake the rest of the day."
What does 50 or so extra calories have to do with anything you eat later in the day? Why has food become torturous? Worry less about those 50, 100, or 500 calories you weren't supposed to eat and think about what all that stress you are putting on yourself does to you.
Stress causes a cascade of hormones designed to prepare your body for hard times. Meaning, those hormones are there to make you fat!! So stressing over 100 calories is really counter productive. Being guilty for indulging in birthday cake is pointless. Exercising yourself silly trying to counter act some candy bar you had is crazy.
We need to stop looking at each individual morsel of food and look at the whole picture. If you are eating chocolate cake everyday then you need to examine things a bit. But if you are having a piece chocolate cake at a birthday party every 6 months then what is the big deal? Eat the cake, enjoy the cake, don't feel guilty because of the cake. It is just food.
One hundred percent dietary compliance is simply not possible. We are not perfect beings. We will make mistakes and make choices that don't fit perfectly with our plan. These things do not make us bad. They make us human. Aiming for 100% dietary compliance is setting yourself up for failure. Why do that to yourself? Give yourself permission to indulge every once in a while. Do so with happiness and joy. You might be amazed by how great you feel!!