The nights are fair drawing in, and there are warnings (issued with an unmistakeable glee) in the papers, of a record freeze imminent. The summer's heatwave seems very far away. I'm reminded of the Calvinist incantation from Lewis, which weaved its way through my childhood. Sun's out? 'We'll pay for it.'

We landed back in the Scottish autumn this year from a holiday in Campania, in the south of Italy. It was an abrupt crossing from one world to another. I was intoxicated by Italy, as all visitors inevitably are. My partner's family had treated us to a week of exceptional food and true Italian hospitality, taking us on myriad tours, from astounding cliff-side towns which tumbled prettily down to shore (Positano, Sorrento) to views of gelato-coloured houses dotted across islands (Procida, Capri).

We were far from Hebridean forbearance here: in raucous Naples I lost myself in narrow streets crowded with nativity figurines, aphrodisiac remedies, and lucky talismans. We touched the golden skull and cross-bones which sits unassumingly on a street corner, and is meant to bring good luck to the attentive; and ate sfogliatelle, a crisp pastry stuffed with sweet ricotta.

Life was being lived, loudly, joyfully, all around us, and at its centre was food. Italian food culture is world famous, yet somehow it doesn't travel well. Outside Italy, the menu has been re-imagined as junk food: gluey lasagne, deep-fried pizza, and pasta boiled to a nursery mush. For the health conscious, there's the oft-recommended Mediterranean diet. I doubt it can be understood through a cookbook or a website, though. A Google search for Mediterranean diet proves that right away: anaemic meal plans, measurements and rules pop up, as if Italian food was a kind of cheerless medicine.

You must live it, under the sun. For example: at road-side stalls, we saw lemons the size of melons. I assumed they were plastic props, but they turned out to be disconcertingly real. In the harbour of Pozzuoli we saw fisherman delivering a morning catch on to the cobbles where customers waited. A crafty octopus tested the surroundings with its tentacles, before making a dash back to the sea (it was caught and returned to its fate; I watched, heart sore for the clever little thing). Food is alive and it is gigantic – and sometimes it moves. Coffee was drunk standing at a gleaming counter, in a spotless espresso bar. A small, wrinkled man on a stool made espresso from a silver machine cluttered with levers. He made mysterious calculations to bring us a dose of black caffeine. Sparkling water from a tap accompanied the hit.

There were the vital ingredients, imbued with heat and sunlight. Then there was the attitude: serious, careful, cherishing. Meal-times were an adamant avowal that we really are what we eat. Everything was tasted by everyone. The vagaries of digestion were a frequent topic of conversation (it was one's due to always feel well). Sought-after foodstuffs and local specialities were announced at the table as they arrived. Meal times were an event around which life's other business would just have to fit somehow. As for individual dietary requirements – a betrayal of the highest order. Eating was communal; it could not be done well in isolation (That part did remind me of the Stornoway scepticism of vegetarians).

When we arrived back home, I was determined that food should have a starrier role in our lives. I enjoyed reading up on the ire of the food writer Elizabeth David, who returned to Britain in 1946, after years spent cooking and entertaining in the Mediterranean. How bleak it must have been, that arrival in one world from another. She had served guests home-made ice-cream in Cairo. Now she was in the country of bed-socks, margarine and Wootton pie. Her summing up of British food is wonderfully bitter: she felt an 'embattled rage that we should accept the endurance of such cooking.' I read of her success in finding 'one pound of fresh tomatoes' in London, under rationing, and taking them home to her sister, who cried, and said: 'I've been trying to buy fresh tomatoes for five years.'

This reminded me of my great aunt Betty, a keen gardener who had an Oxfordshire Eden of roses and raspberries. She mourned for good tomatoes. 'We used to eat them on toast,' she had said wistfully, 'without any seasoning. They used to taste so strong.'

In Italy, we had been served tomatoes from someone's garden. They must have been loaded with salt and pepper, vinegar – herbs? I wondered as I munched. Our host confirmed there was no seasoning on these tomatoes. She was confident that the taste came from 'the garden, the sun.'

So I began, in Scotland, with tomatoes. No more of the watery, limp things that supermarkets sell in plastic trays. I ventured in to the only greengrocer in Musselburgh and found yellow and red plum tomatoes piled up. 'My kids eat these like sweets,' said the man who sold me a paper bag full. I knew then that I was on a to a good thing. We savoured them in a salad with basil. Good news for a season of bad news: the prelapsarian splendour of the tomato is not lost yet.

A steady feast of fruit and vegetables won't be enough to protect us from the Scottish winter's sharp edge, I know. Luckily, southern Italian cuisine caters for the Scottish palate surprisingly well. Perfect for a winter's night is gatto (not the word for a cat, but a more guttural, savoury musing on the French gateaux), a smooth, melt-in-the-mouth potato cake, rich with melted cheese, eggs and meat. On cold mornings I've turned to another Italian discovery: biscuits for breakfast. As unlikely as it seems, Italians opt for wafers and Nutella-loaded biscuits dipped in milk. What a perfectly wayward start to the day. It would make a nutritionist feel faint.

Yet this is perhaps the heart of the Italian love for food. Food is comfort and joy. Food is there to make you feel good. Enjoyment is to be taken seriously, every day. One chilly morning in the kitchen: 'I'm on the Mediterranean diet now,' I announce, opening a bag of chocolate Pan de Stelle biscuits. 'It's wonderful for the mood.'