Exercise is a cod. It’s the ultimate global deception.

The reason is that exercise and eating are not two sides of the same oversized coin.

Despite their billing, they are not equals. One is a heavyweight, with the ability to turn people into lightweights; the other is exercise.

Eating habits matter far, far more than any exercise routine. The balance isn’t even close.

With television programmes about losing weight again in vogue recently, the emphasis is almost always skewed towards exercise – or, at the very least, given equal billing with eating habits. But then how boring would these programmes be if, instead of participants sweating on treadmills, they were simply filmed not eating high-calorie foods?

Every chocolate bar I’ve picked up in the past few days has contained between 400 and 500 calories. (No judging, please, it was research.) I’m told the rule of thumb is that running a mile burns 100 calories. That’s right: 100 calories.

Not 1,000, as you might demand, all being fair in the world. That’s a lot of miles just to erase the memory of one chocolate bar.

That’s not to say that skipping the chocolate bar and the weights bar will make you fitter, or stronger, or give you a six-pack. It won’t. And eating more healthily is not a legitimate excuse not to exercise, whatever we would all like to believe.

However, it appears that to balance the effect of a chocolate bar, you need to jog around the Himalayas twice carrying a Sherpa on your back. And that’s just the fun-sized bar – anything bigger and you’d need to stand at the top of Everest. Or . . . you could just not eat the chocolate bar.

When it comes to time, energy, willpower and money, diet is the easier answer when it comes to a choice between the two.

Calories and weight are not inversely proportional, but they are as good a yardstick as any, especially to a non-expert (a polite term for an ignoramus) like myself.

It’s easy to understand, though far more difficult to live by.

Goal: Lose weight.

Method: Create a calorie deficit.

Notes: By my amateur count, my body uses about 2,800-3,000 calories each day to maintain my oversized body. Losing around 0.45kg/1lb a week would require a 500-calorie daily gap between calories used and calories devoured.

Option one: Diet. Keep calorie intake below 2,500 each day. Avoid eye contact with chocolate bars. Not exactly a near-starvation diet by any stretch of the imagination.

Option two: Exercise. Run 4 to 5 miles every single day.

Conclusion: See option one.

Simplistic, but then, that’s the only language some of us understand.

* In March 2015, Damian Cullen decided – for the 453rd time – to embark on a fitness and health drive, detailing his progress in a regular column in The Irish Times. The main catch was that there could be no radical alterations to his life. Losing weight was a secondary (though much-needed) goal; improving general health was the primary focus. Twelve months later, he was 15kg/2st 5lb lighter.

But the battle continues.