When I was a little boy, I ate a lot of sweets. And by ‘a lot’, I don’t mean I rounded out every meal with one, but that I often had meals that consisted of nothing else. When I think back on it, I suspect I had some sort of mild psychological addiction to them. How else can I explain the ridiculous lengths I was prepared to go to in order to get my fix? It wasn’t unheard of for grandma to bring out the box of chocolates she was keeping for visitors only to discover that the exact number were missing that would fit into my hand were I to stealthily prise the lid open just far enough for my little fingers to mount a raid on the contents. I was prioritising before I was pronouncing: “Don’t want soup!” I’d cry. “Want candy!”

For all that, I never put on an ounce of weight all through my childhood. Even when I joined the army I had a BMI of 20.6. So what’s changed? Every time I give my imminently middle-aged body a week off, my weight admonishes me with an extra kilo! Nutritionists are quick to answer: carbs, especially sugar. And if I ask them why, in that case, I never put on any weight as a kid, they have the answer to that one, too: my metabolism’s slowing down.

The half of my brain that contends with logic has always told me it’s all a con, since glucose fuels our bodies. Nutrients can only be proteins, fats or sugars. Whether we’re eating chocolate, potato or yoghurt, the body uses every biochemical trick up its sleeve to break them down into glucose. In the grand energy plan the only difference is the speed at which those things are broken down – or to put it in layman’s terms, how quickly we feel hungry again.

What follows is something my six-year-old niece helped me put into words. It was her birthday party, and first course at the party table – sandwiches on sticks – was done and dusted. We not-children standing by the table devoured the remaining courses with our eyes, salivary glands gunning to process some glucose. One dad even let his belt out a notch, and that was before he’d eaten anything. But we were the only ones at the buffet. “Lisa,” I heard my sister-in-law holler above the pandemonium, “aren’t you hungry?” The six-year-old answer, when it came, struck me like a bolt out of the blue, and ran through everything I’d known and the very way in which I’d thought about things to that point in my life. “I am, but I’m playing with my friends! They have to go soon!”

The reason I could eat my own bodyweight in sweets as a kid and never gain an ounce wasn’t because I had some mind-blowing ninja metabolism; nor was I any more active than your average child. It was because everything I did was with a sense of playfulness and excitement. As bizarre as it must sound to an adult, it was as though I existed in this unending flow state where life was about nothing more than the pursuit of happiness.

The sweets had nothing to do with my weight, since I didn’t always reach out and grab a handful of them as soon as my stomach nudged me and said, “Hey, what about me?” I’d be out kicking a ball around with the other lads until the sun set, and even though I might’ve been hungry, my answer was always the same when anyone asked if we fancied another game. I simply knew that a growling tummy and feeling tired were OK. They weren’t an illness that needed to be treated right away. And isn’t that the highest level of awareness that’s coded into us from the very beginning – but which as adults we tend to forget?