PSA: A nutritionist and PT told us exactly how long you can slack off for over Christmas.

Christmas is coming – in fact, it’s days away and there’s something we need to talk about before embarking on our usual Christmas and Boxing Day feasts.

Our Christmas health. Ugh.

It’s called the silly season for a reason – most of us use the holiday as an excuse to put our healthy lifestyles on hold for one, two, or 30 days in favour of chucking as much food and liquid down our gullets as possible.

Which is fun, at the time, but then comes the dreaded ‘new year, new me’ phase of trying to convince your body that binge fest never happened. It’s not that great for your mental health.

Basically, what we wanted to know is, how much time of eatin’ and drinkin’ do we have before the hard work (because being healthy is hard) we put into our health over the year starts to come undone?

Can you really ‘undo’ a years’ worth of burpees and probiotics if you binge for a few days (or weeks) over Christmas? And do we have the green light to slack off for a week or so?

To find out, we spoke to celebrity nutritionist and founder of Falling in Love with Food Zoe Bingley Pullin, and personal trainer and 28 by Sam Wood founder Sam Wood so you can go into Christmas Day and beyond feeling at peace with how much you’ll put into your body.

When it comes to the food and alcohol bit, Bingley Pullin said whether or not you’ll put on weight over Christmas comes down to a) how much you consume and b) your metabolism. Makes sense.

“For the average person, they are likely to gain some weight but provided they go back to their usual eating patterns and don’t continue eating at an increase in calories, their weight should normalise,” she told Mamamia.

“The time frame taken to return ‘back to normal’ will depend on the extent to which they overeat and how much weight was gained. If not much a week or two should see them return back.”

Side note – thinking of giving up booze in the New Year? here’s what might happen to you. Post continues after video.

Short term, the affect going from a somewhat restricted diet to over eating will have on your body is more about how you’ll feel.

“If eating clean and then suddenly not so clean, you will likely feel a bit off following unhealthy meals and appetite may be low following the meal or for a while after,” she said.

“High fat foods can cause digestive upset, specifically nausea and loose bowels. If you’re suddenly eating more sugar, you may feel more flat overtime because you will get the initial sugar high which is shortly followed by a crash. If you have taken a break from alcohol and then hit it again over Christmas, you may lose your tolerance for it so when you start drinking again it will take less alcohol before feeling its effects.”

Bingley Pullin also warned the week after Christmas won’t be as fun as doing the damage was – expect to feel hungry and bloated, and some, erm, different bowel movements.

“Food wise, if you have been on a restricted diet and then start to binge, the body will not be used to a high volume of food and unless you stop when satisfied, it will likely lead to feeling full very quickly, nauseous, bloated and may cause a change in bowel habits. Initially you may have more energy but it may be followed by feeling sluggish soon after,” she said.

“When you start restricting again (i.e. after Christmas), you will feel quite ravenous for the first few days until your body gets used to the decrease in food. Energy levels would likely be quite low for the first few days also.”

In short – a week of indulging won’t ‘undo’ your nutrition, but it’s important to go into the period telling yourself that yes, you are allowed to eat food with your loved ones over Christmas without feeling guilty about it.

“We say it all the time, but let go of the all or nothing mindset and know that everything in moderation is perfectly fine,” Bingley Pullin said.

You can do this by:

• Enjoying the entire experience of eating food – not just the taste, take time to smell the food, touch the food and eat the food in a relaxed way.
• Eating mindfully away from distraction – look at your food, be thankful for it and eat food slowly feeling the textures and tasting the food.
• Celebrating with foods you truly enjoy and look forward to eating – not just the ones that are in front of you.
• Sharing food with loved ones – look beyond health and weight and focus on the positivity of bonding over food.

Same goes with exercise, and that’s exactly what Wood tells his clients who are worried about undoing their fitness work with a week or two off.

“Our bodies are amazing things, they adapt, and adapt fast. So don’t beat yourself up over a missed workout, a bad week, a crappy meal… you can recover,” he told Mamamia.

“However, what goes in must get burnt off, and if you have a goal to be in great shape early in the New Year, it will be hard to achieve if you go backwards during the Christmas period. If you can break even during this incredibly busy, social time of year, that’s great. Life is to be enjoyed.”

Fitness-wise, Wood said regular exercisers will be able to get away with a break from training for longer, however, a month off from exercise doesn't mean an extra month on to get back to where you started before Christmas.

"In a week, you'll notice little to no changes, but second week, that's where you'll start to go backwards, and after a month, you really will feel it. That said, you might go backwards fitness-wise in a month, but you'll regain that in seven to 10 days, so it's not a month for a month to get back to where you were, which is good news."

The advice Wood gives his clients for tackling fitness during the Christmas period is to be realistic. You will not go for an hour run every single morning. You can do 15 minutes of high intensity interval training (HIIT) every second morning, though.

"I believe no one has an excuse not to be able to achieve 15 minutes of exercise every second day, and in most cases, that will be enough to break even. Something is better than nothing, but doing a short HIIT workout with squats, jump squats, mountain climbers and burpees over a 20-minute brisk walk will get you more bang for your buck."

"You can do it in the spare room, you absolutely don't need a gym, body weight exercises are totally fine. Do it in the morning, then it's done. Even if you have a boozy lunch, you come out of that day breaking even."

To recap, the main message from both experts is this:

Health, nutrition and fitness aren't set in concrete. No single day, or in this case, a week or two will send you right back to 'the start'. Just like life, it's more of a one step forward, two steps back kind of situation, and the best way to avoid 'undoing' your hard work is to keep the Christmas period in perspective.

Enjoying a week of glazed ham, Pavlova and Prosecco isn't failing.

Just get right back into it the following week... and expect those first few burpees to be a tad tougher than you remembered.

Do you have a strategy for staying healthy(ish) over the Christmas break? Tell us in the comments!