Ah, Boomka.

Where were we before we were so rudely interrupted?

Oh, I remember!

Two years ago in this very spot, I was calling you "Fatty Boomka", in reference to the fact that "you fat bastard, you fat bastard, you ate all the pies" – and , since your late 20s on, have let yourself go something terrible. And you were telling me to shut the hell up and stop going on about it, because you were just about to start this amazing diet you've heard about that will strip the kilos off you in no time! And soon, you said, you were also going to stop drinking so much, and as a matter of fact had even bought an exercise bike!

I sneered unpleasantly, and said it won't work Fatty Boomka, because you just don't get it any more than those tragic boneheads who buy wobble-boards from late-night television, and actually believe if they stand on it, they'll lose weight. I said, Boomka, firstly, you have to get it through your thick melon that "The aim of the game is NOT to go on a diet, it is to change your diet."

I ranted, with the unfortunate zeal of the reformed smoker, at you how it is actually much easier to STOP your drinking entirely than merely moderate it; and then carried on until your nose bled, about how while it is one thing to buy an exercise bike, much more crucial is to actually use the bloody thing.

I said I can get away with such aggro, "fattist" language because firstly I used to be you, and secondly my theme was that if you are serious about getting back in shape, your starting point has to be to cut the bullshit in every sense of the word. I said if you're offended by this frank language, too bad, stop reading. But if you are serious, toughen up, and read on.

I said, it is dead bloody simple, once you understand it.

1. Get off the bloody sugar, dickhead, because it's killing you. It's in every damn bit of processed food you eat, makes you hungry all the time, and – to use the medical term – completely roots your system. (Quoting David Gillespie's seminal book Sweet Poison, I pointed out how your great-grandparents had two kilos of sugar a year as the normal, natural human intake, while you have 50 to 60 kilos of sugar a year, as an average Australian, so how can it not be rooting your system?) Once you make the choices to only eat fresh food – distinguishable by the fact it doesn't come out of a packet, or jar, or box, or through your car-window – your appetite normalises, your energy levels go through the roof, and the weight falls off you, naturally.

2. Stop being a piss-head. Beyond everything else, all the times you exercised bad judgment while under the influence – "Yes, as a matter of fact, your bum does look big in that" – all the times you'd made a complete dick of yourself, all the money you've pissed up against the wall ... there is a solid dietary reason to quit. See, once you understand that every bottle of wine has as many calories as a Big Mac, everything comes clear! For me that was the thing that got me completely off it, and it was best personal decision I've taken in decades.

3. Get your arse moving, every day. We are not meant to be sedentary slobs. We are meant to move. So you have a very simple choice: move it, or lose it. And if, as an over-50 Boomka you need a reason to focus, try this: how many obese 75 year-olds do you see around? In my case, I can count them on the fingers of one finger. Just about all of them cark it, well before that. So, decide! Do you want a long, active life? Or do you want to finish it, dully, in an unending series of doctors' waiting rooms?

I said, and I meant it, all of the above can be summarised in 10 words, which should be your new mantra: "Don't eat sweet, don't hog grog, and bloody well MOVE!"

You told me to get nicked, you'll do it your way and I told you that you will remain a Fatty Boomka.

And so, two years on from that column, which turned into a best-selling book called The Great Aussie Bloke Slimdown, how are we both going?

Well, you, from what I can see, are struggling. You're talking the talk, as ever – telling everyone that 2018 is your big year, you're starting now, you're going to get fit, blah, blah, blah. But your friends and family have heard it all before, haven't they? They don't believe you, in large part, because you don't believe you. You're still going on with the same blah-blah as the seasons change and you just keep getting bigger.

But me? Well, I don't like to boast. No, really. But, the short answer is, "Bloody well, thanks for asking".

From playing Test rugby at 114 kilograms in 1990, and blowing out to 152 kilograms in 2012, I went down to 106.9kgs – once, totally dehydrated after five sets of tennis. I have now settled into the 112 to 115 kgs range. Despite the occasional blow-out on sugary things, I remain absolutely rigid on alcohol. Most amazingly, I've even lost my taste for grog, and am a different man.

No kidding, in late January I was out on the Birdsville Track in a rented Toyota four-wheel-drive, on the path of Burke and Wills for my latest book when, with my young researcher, we blew a tyre. This was dangerous, as we had not seen another car in two days. So, in crippling heat, for 90 minutes, I was reduced to doing the lowest thing an Australian male can do – something that, in the desert heat, was just one up from having to drink my own urine. Yes, it's true, I had to read the instruction manual! I had to through the complicated process step-by-step for a 4WD, as to how to find the tools, extract the spare tyre, jack it all up and change tyres etc. Once accomplished – we were saved! – we got back on the road, and Libby offered me an ice-cold beer. "No thank you," I said, lightly. "I don't drink." And I meant it. Only afterwards did it occur to me, how weird it was that one who drank as much as I did, and loved it, could have precisely nointerest in having a drink in such a circumstance as that.

The biggest change for me, personally, is that I am more than ever into physical activity. A coupla years ago, as I have already recounted in the SMH – ad nauseam, I acknowledge – a mate insisted I go to the local gym with him for a session with his trainer. It was a shocker. Hated every minute of it, with the saving grace that as it was only 30 minutes, nothing much was lost. And when the trainer called a few days later, I did reluctantly agree to go back, and found, to my amazement that I could bench-press a little bit more than before, and was just a tad more flexible than the "pathetically rigid" rating I had received on the first go. Before long, I was hooked, and on days when I didn't go, felt like a miserable slug. Somehow, even though 25 years on from the prime of my football career, that drive for intense physical activity was there, as was – and this is what really amazed me – a fair chunk of my one-time physical strength.

And then something else changed.

About June, I started to get interested in those indoor rowing machines I had previously sneered at – a sneer that came in part because I had never rowed seriously. But then, I started measuring how many metres I could row in 60 seconds; how long it took me to row 500 metres or 2000 metres, and found I was competitive with others my age.

To my amazement, in August, I won the NSW Indoor Rowing Championships in the over-55 section for the distance I could row in 60 seconds of fury. On the strength of that, I entered the National Indoor Rowing Championships in November, to see how quickly I could row 500 metres. In the end, I did it live on Channel Nine's Sports Sunday, knowing that to win the gold medal I needed to do the distance in 1 minute 26.5 seconds; to get the Australian record I had to crack 1 minute 25.9 seconds, while the fastest time in the world for my age group this year that I could find was 1 minute 23.7 seconds.

I was ready. I had done the work. I had had my heart checked by professionals. Go! In the end, I did it in 1 minute 23.6 seconds.

And thus, my advice to you, Boomka?

Give this another go.

This year, instead of just talking about it, actually do it. Find a stringy 70-year-old whose energy levels and life you admire, and start to live, eat and drink like them.

Listen, here's the secret. When it comes to sugar and grog, for most people, you actually only need to show real discipline for a few weeks, until you lose the taste for it, and after that, eschewing those two demons just becomes a healthy habit and most of the rest of it takes care of itself. Take up a physical activity, and go hard at it. Measure your times, or distances. Beat them. The younger, active version of you is still there, you just have to dig that version out.

The best news of all? Yes, you've abused your body for a couple of decades or so. But it doesn't take that long to get back in shape. Your body is an elastic band. It wants to get back in shape. If you give it that chance – with your doctor giving the OK if you're in any way at risk by too sudden a change – in a week you'll notice a difference, in a month your friends and family will, and in six months you'll be you again.

Go for it!