A new study has found that it takes depressing three months to shed off those extra pounds piled on over the festive period.
According to research by MSN, for Christmas lunch alone the average Brit feasted on two to three servings, consuming 2,300 calories across one meal.
That accounts for 115 percent of the recommended daily intake for women, and 92 percent for men - and that's before taking into account the nuts, chocolates and alcohol people consume.
Nutritionist Dora Walsh said the key to not putting on weight over Christmas might be to eat slowly.
"You can still enjoy your food at Christmas without going overboard and gaining weight," the Daily Mail quoted Walsh as saying.
"They key is to eat slowly and enjoy what you are eating without over filling, and also stay active over the Christmas period to help burn off any excess calories.
"It's about moderation, which will help avoid the extremes of gorging at Christmas and starving after.
"Any post-Christmas diet plan needs to be sensible and balanced because crash diets don't work and quick fixes won't last," she added.