It helped me when I was beginning to set the intention of retraining my tastes, portions and approach to food. I became a vegetarian and worked to eat mindfully. I reminded myself that one small bite of anything was all I needed to know everything about it's taste, texture and to savor that small amount.
It is easier to substitute wisely at home. You may also think about other things when attending events like what you can bring to the conversation. Sometimes I take a camera so I can be busy taking candid photos instead of focusing on the food.
Let your past weekend go and move on making steps in the direction you want to go.