The author - nudging 150 kilograms - with son Jake, daughter Billi, and wife Lisa. So do you want to hear the answer, or not? Bloke to bloke, no bullshit, no touchy-feely crap, no "miracle diets" nonsense, no Jenny Craig, no self-mutilation by taking out half your tummy, or putting in staples. Ok, here goes ... Several things happened to me that changed me forever. First up, my wife told me straight out: "Pete, you're too heavy."

Around the 114-kilogram mark in club rugby days. Credit:Sue Windmiller At least I think it was her and I think that's what she said. At the very least, there was a certain muffled voice, just like hers, coming from somewhere way beneath me, and it said something a lot like that. I checked, and she was right. From my weight of 114 kilograms playing Test rugby – I know, I know, I'll have to tell you about it some time – I had gone up to just over 150 kilograms, and was now living the cliche of the former fit footballer turned to fat. Sure, I had gone up and down many times as I got serious about my weight, but this was a post-war high. Lisa had a point. The post-booze model. Credit:Nic Walker I read a book, David Gillespie's Sweet Poison. There's a bit of mumbo-jumbo in there, but the premise is very simple: sugar is killing us all. The more processed a food or drink product is, the more sugar they whack into it, simply so they can sell more. And the problem is not just the calories those sugary food and drinks add, but how hungry it makes you for everything else, how, after the first Tim-Tam, you're immediately hungry for a second and third, not to mention – after that delightful afternoon snack – a much bigger dinner. If you only take one thing from this rant, take this, from Gillespie. The average Australian and American consumes 40 teaspoons of sugar a day, adding up to 1.2 kilograms of sugar a week, which translates into 60 freaking kilos a year! This is all the more shocking when you realise the natural intake of our ancestors – the amount our body actually needs – was 1.3 teaspoons a day, about two kilograms a year.

So this is the first thing you need to get through your fat melon, Boomka: Stop the sugar, stop the hunger. Bingo! I grasped that simple fact, and the rest started to come good. Illustration: John Shakespeare Stop the processed food and drink, and you stop feeling so damn hungry all the time. Try it. It is a revelation. I haven't had a soft-drink or processed fruit juice since reading Gillespie, and that was a big leap forward. And then the next breakthrough ... Sweet Poison, oddly, didn't go too much into the dangers of grog, so I sort of gave myself a free pass on that, and could have drunk wine for Australia. On September 14 last year, I was doing pretty much that. I had driven all day down to Thredbo to pick up my second son, and was having dinner with my mate Jordan Rodgers, who runs the whole shebang.

I had polished off the first bottle of wine after 10 minutes, and was calling for a second, when I said, curiously, "You're not drinking, Jordan?" (Translation: "Call yourself my mate, an Australian male, we're catching up, and you're not on you're way to being pissed as a newt, just like me? What is wrong with you?") "No," Jordan said, "I guess, running Thredbo, I feel I should bring my 'A' Game to it." Bingo! I thought about it. The next day, I tried to ski with my lad. Now, as you know, Boomka, for Fatties like us there is a very fine line between what others call "skiing" and you and I might call "Trying to get the f--k off the mountain!" I came down, feeling old, fat, and slow. What to do?

Of course, the obvious. I did what you and I have always done whenever feeling a tad low and slow. I had a huge meal that night, and got pissed as a newt! That's the way we roll, am I right, Boomka? Still, why not try stopping grog altogether? I gave it a go. Starting the next day. Didn't have a single sip of anything alcoholic. Strangely, I didn't miss it a bit. Went to several lunches, and one dinner that week, and again, oddly, I just felt virtuous, as those around me started slurring their words in, let's face it, a most pathetic fashion. (Please tell me I didn't used to do that, did I? I did? Well,sorry.) By the next Saturday night, it was my eldest lad's 21st and after a stone-cold sober speech, I lifted the glass, filled with champagne. "Here's to Jake," I cried cheerily, as the song-throng all joined me in the toast. But this was the moment, and I somehow knew it. (And you know it, Boomka. Because you and I are cut from the same cloth.) If I had just one sip, it would have been ridiculous not to have two sips.

And if you can have two sips, why not four? Why not the whole glass? Of course it wouldn't hurt to have two glasses, because if one glass of grog is nice, two glasses are great, a whole bottle is fabulous, and with two bottles in me, I always had the time of my life. At least I think I did, if only I could remember it. But it all goes by in a bit of a blur, doesn't it mate? I resisted. Didn't even have a sip. Haven't had a sip of grog since. And I won't, until the night Australia grows up and becomes a Republic, but that's another story. The upsides of stopping grog completely? Let me count the ways!

1. The weight just falls off you. Each bottle of wine – and this is a revelation I have encouraged Gillespie to include in forthcoming editions – has the same calories as a Big Mac! This, oddly, was a revelation to me. How many times have I had a three-course lunch at Machiavelli's, washed down by a couple of Big Macs, and then wondered why I had turned into a Fatty Boomka? 2. You really do bring your A-Game to everything. You think clearly, need less sleep, and are twice as productive. You are much less often a bad-tempered prick, and I mean that. (I never used to think grog affected my moods, but now I get it. It did.) And restaurant bills, seeing as you ask, are about half. 3. Brownie points! Happy wife, happy life. Even when Lisa is pissed off at me for something, I have so many Brownie Points in kitty for being 34 kilos lighter than I was, and 100 per cent sober all the time, and more pleasant to be with, that we get through it quickly.

(Part of it is, that as I am sober, I am no longer inclined to tell her, wit' shum detail, now you lishen to me ... a few things she desperately needs to be told!) 4. You get it through your thick noggin, at last: while it is a better night with grog, it is a better life without. And I dinkum don't miss it. So, to wrap it up. As you go into this new year, if you are dinkum about losing weight, sobering up and all the rest, what you have to do is this: You have to rely not on your will power, because that is hopeless. Sooner or later – by which I mean two days, max, Boomka – you will fall back into your old ways. No, you need work with parameters, you set yourself.

See, you know how – now you've given up smoking – you don't even think about having a cigarette any more? Well, you need to do the same with soft-drink, biscuits, grog and – for me – the huge slabs of red meat I used to plough through, but now no longer do. You don't need to do the tedious calculations every meal time about how many calories are on the plate, because who bloody well wants to live like that? Instead, try this for a simpler calculation: don't put your left blinker on when you see golden arches, lose 6kg; stop drinking entirely, lose 10kg; stop biscuits, lose another 5kg; stop soft-drinks and go down 6kg in a year! Etc, etc, etc. The reason you turned into a Fatty Boomka, is because, like me, you have a certain obsessive streak. All you need to do is steer the obsession towards a different, better goal. The best thing of all. You can bore your friends rigid, with how much better everything is! And not just your friends. Everyone. So, to wrap it up. As you go into this new year, if you are dinkum about losing weight, sobering up and all the rest, what you have to do is this: Face the truth - the elephant in the room, is YOU.

Oi! You. Fatty Boomka. Yes, you, I am talking to you ... Twitter: @Peter_Fitz