Happy Happy and Merry Merry can easily turn into ate too much and feeling yucky. Remember the remedies, kudzu tea, umeboshi, mint, homeopathics, etc... for those moments you need a little extra support. Ask your coach for specific ones for your specific trouble.
One of the best prescriptions for staying well and merry, is eat less. Even in the face of more more more being paraded under your nose. It's fine to enjoy a little extra treat if your stomach isn't already so full from the previous meal. Remember, many foods take hours to digest. So eat lightly and try just one cookie instead of three. When you eat lighter, it taxes your whole system less and it becomes more efficient. Then there is more room for a snack or two when you want to sip, crunch or enjoy the joy of holiday foods.
Cut down just a little on each meal can have a large impact. I you usually eat 1/3 of a cup uncooked grain for a meal, (cooked of course in a cup of water) try having a 1/4 cup instead. If you use 1/4lb turkey in a sandwich, go for a little less and a lot more veggies. Get creative and watch how easy it becomes to realize you are satiated, just not stuffed... Then there is room for a little treat here and there.