Nutrition and dietetic centre dietitian Miriam Mullard said, on average, people gained between one and two-and-a-half kilograms over the silly season.
Healthy choices - such as starting each day with a healthy breakfast - kept hunger pangs at bay for the first half of the day. Five a day could be helped by lashings of seasonal fruit.
It was easy to overindulge at Christmas, but little tricks could help, she said.
"If possible, keep treats out of sight, and have healthy options on hand to keep temptation at bay. Try a handful of unsalted nuts, dried fruit, plain popcorn, wholegrain crackers or pretzels."
As for pouring down the throat, the message was less and more. Less booze, more water. And if you must indulge, make sure you're on the solids as well.
Professor of Public Health and Social Research, Sally Casswell, said the time had come to celebrate Christmas without a hangover.
"Why do we live in a country where hangovers are so ordinary, even funny. Where radio hosts and companies use them in advertising?
"Hangovers are a sign that so much alcohol was drunk the neurotransmitters in the brain stopped working normally, the stomach lining was inflamed, blood pressure increased and the body's ability to fight off infections was reduced for 24 hours."
Other tips included making sure enough shut-eye was had, especially before long drives, always having condoms with you, setting a firm cut-off time for gift buying to avoid last-minute budget blowouts and supporting the bereaved.
University Meditation Service Manawatu director Virginia Goldblatt said the gift of peace also had a place under the tree.
Negotiation and conflict resolution skills learned in the workplace could be used on those nearest and dearest to us who showed up late, or lacked gratitude for the time and trouble taken with the Christmas celebration, Ms Goldblatt said.
Twelve days of Christmas survival tips:
1. Exercise in disguise - playing with the kids or tackling the garden make keeping fit fun.
2. Don't let the party turn into the hangover from hell - drink in moderation, and with food.
3. Avoid a Christmas drought or drowning by drinking plenty of water. If your pee is clear though, pull back, you're taking on too much fluid.
4. Savour your food and be aware of what you're eating - only eat what you want to eat, this is the time to enjoy your favourites.
5. Remember the three Cs for a food poisoning-free Christmas - cook, chill and clean.
6. Rest those weary eyes. Get plenty of sleep, especially before driving.
7. Practice safe sex. No one wants an STD for Christmas.
8. Avoid the holiday debt trap by budgeting for gifts and ban last-minute buying.
9. Don't put on a brave face this Christmas. Support those struggling with grief or depression.
10. Give the gift of peace by avoiding conflict.
11. Stay sunsmart, but get some sun in the early morning or late afternoon to keep vitamin D levels up.
12. Grown-ups, leave the kids' toys for the kids and avoid a summer injury.