As Kiwis recover from a Christmas and summer break likely full of alcohol and barbecues at the beach, one woman believes she's found the secret to giving up - or at least cutting back - on drinking.

Former marketing executive Annie Grace tried to develop a tolerance to alcohol so she could keep up with her colleagues.

She got to the stage where she was drinking two bottles of wine every night. And when she started to "not even feel it", she knew it was time to stop.

Her new book, The Alcohol Experiment, takes readers through 30 days of not drinking, providing tips and tricks for each day.

She believes "magic happens" in 30 days. It's a period of time where the brain can build new habits (or eliminate old ones). At the end, participants have changed their relationship with alcohol and given up, or at least cut back.

Grace says she lost 5kg in her first 30 days and was happier in social situations as she never worried about what she'd said the night before.

She eventually left her marketing job to run the website This Naked Mind and its weekly podcast. Her first book, of the same name, explored the reasons why we drink and her own relationship with alcohol.

She is now alcohol-free and lives with her husband and three children in the Colorado mountains.

Grace warns of side effects as the body cleanses itself, including cravings and irritability and is clear that people with a strong physical addiction should seek professional medical assistance.

In an extract below, Grace talks about how to get through day one of the challenge.

Getting started

Magic happens in 30 days. It's a period of time when the brain can actually change — by making new neural connections — to build great new habits or to eliminate habits that have held you back.

But to experience that magic, you may have to deal with a few side effects. After all, alcohol is a toxin and your body needs to cleanse itself. You might experience some cravings and irritability at first. This is completely normal and will pass as the alcohol leaves your system.

It takes about a week for the body to detoxify itself, so be gentle with yourself during this period. Once your system is clean, you're going to feel amazing. You'll have more energy. Your brain will feel like a fog has lifted. And it's possible you'll feel happier than you have in a long time. Here are a few things you can do to help the process along.

• Make a firm decision to commit to this experiment 100 per cent.

One firm decision takes all the stress out of the thousands of smaller decisions you have to make every day. You want to burn the boats here like there's no going back. It's only 30 days. And at the end, you get to make the final decision about whether you continue on alcohol-free.

• Tell someone you trust about what you're doing and why.

It's okay if you don't want to announce it to the world quite yet. But there's incredible power in having someone you can confide in. Do this and you're much more likely to follow through with the whole 30 days.

• Drink plenty of water to flush out all the toxins in your system. The more you drink clean, pure water, the faster your body can cleanse itself.

• Get lots of sleep.

Your body repairs itself when you're asleep, so give it all the time it needs. If you're worried you won't be able to sleep without drinking, we'll cover that later in the book.

• Get some exercise.

You'll feel better when you get your blood moving. And I've found vigorous exercise to be a great way to overcome both cravings and irritability.

• Eat healthy foods, especially protein. Your body needs protein to make amino acids, which help elevate your mood.

• Start a journal.

You're going to want to "talk" through what you learn in this book, and a journal is a great place to record your thoughts privately. You can use an app on your phone, make a video diary, or use good old-fashioned pen and paper.

If you sign up at alcoholexperiment.com, you'll get a private daily digital journal. It's a great way to keep track of your amazing progress.

• Take a photo and weigh yourself.

You might be surprised at the differences you see in your physical appearance after 30 days without alcohol.

• Stay social.

Now is not the time to isolate yourself or lock yourself away from your friends and family. You need your social life. You need your friends. You might be nervous about going out to places where you regularly drink. But this is an experiment. You have to get out there and try it.

You are experimenting with how your real life will be without alcohol. As you go along, you will be amazed to realise you don't need alcohol to socialise or have a good time. You only thought you did.

Think back to when you were a child or in high school — did you need alcohol then? Weren't you having the most fun? And what's the worst that can happen? You go out to happy hour, you order a refreshing glass of iced tea, and you have a miserable time. So what? It's just one evening, and it's all part of the experiment.

That is great data. You can examine exactly why you had a miserable time and whether the lack of alcohol is truly the reason. I bet you will surprise yourself by having an amazing time.

• Be positive.

Many people tell me their biggest fear is they don't think they can do it. They aren't sure they're strong enough to make it 30 days. Don't kick off this experiment by feeling sorry for yourself. You have so much to look forward to.

Sure, the cleansing process takes a little while and it's not entirely pleasant, but you are strong and you can handle it. The same people who thought they couldn't do it write to me after a week or two to say they can't believe the difference in themselves. They now know they are stronger than they thought.

Day one

We've talked about how you've been unconsciously conditioned to believe alcohol is a vital part of life for relaxing, socialising, and everything in between. And you know there are competing desires inside your mind.

Your conscious mind wants to drink less, or even stop drinking completely. And your subconscious mind believes you need to keep drinking for some very good reasons. Before we dive into those beliefs and stories and deciding if they're true, we need to know what those beliefs actually are.

After reading literally thousands of stories from people who've gone through this process, I'm pretty sure I know what your beliefs are. But that's not important. What's important is that YOU know what they are. So let's start this experiment by writing a list.

Write down a list of every reason you drink. There's no judgment here. We simply want a list.

To get you going, here's a look at part of my list. You might have some of the same reasons.

• Work is stressful and drinking helps me relax after a long day.

• Drinking helps me be more creative on the job.

• Drinking helps me be more outgoing at networking events.

• Drinking is important to my social relationships.

• I love the taste of wine.

Don't stop with a few reasons; keep going until you can't think of any more. You might come up with 50 or 100 reasons, and that's fine. You've brought your subconscious beliefs up to the surface of your mind. Now we can shine a light on them, examine them, and you can decide for yourself whether those beliefs are true.

And you can make that decision based on the facts, not social conditioning from the media and your peers. Don't do anything with this list right now. Don't try to change your mind. At the moment, these are your beliefs, and they're currently true in your life. As I present you different ideas over the next 30 days, you may think about this list differently.

Okay, next I want you to pull out another piece of paper and make a second list. Write down all the reasons you want to take part in this experiment. WHY do you think you might want to drink less? Here's a peek at my list:

• I'm tired of waking up slightly hungover.

• I no longer want to worry that I said something stupid the night before.

• I am sick of the internal dialogue about my drinking—I am tired of thinking about drinking.

• I saw a photo of myself out with friends and my teeth looked purplish from wine —it was disgusting.

• I look back on certain days and my memories are so fuzzy. I am afraid I am missing my life because I can't clearly remember it all.

Today, read over both your lists and notice how they are in conflict with each other. This is the whole source of your cognitive dissonance. It's the battle going in your mind all the time, written in your own words.

Over the coming weeks, it might help you to picture these lists on either side of a seesaw or a balance. Right now, the first list might be longer than the second one. In a few weeks, check back in to see if the balance has shifted at all.

The Alcohol Experiment

RRP $29.99

By Annie Grace

HarperCollins Publishers