I often find it a struggle to eat enough on feast days - I think it's because I'm carrying over the willpower from the fast day. I also think it may because if I fancy something on a fast day I tell myself 'I can have it tomorrow' and apply that every day!

As well as using a smaller plate/bowl I use a smaller fork/spoon - not children's size but just a tad smaller than usual so it's not noticed by anyone else.