My quest is over. Not for me the pointlessness of climbing mountains just because they are there, or running marathons for the sake of running marathons. Over the past few months, I have dedicated myself — and my body — to a far more important and worthwhile task.

I have eaten.

Not just anywhere. I have been on a quest to discover the finest restaurant in the world. I would like to be able to tell you that I had the idea of benefiting humanity in some way as my driving force, or that there was some other deep purpose underlying my task. There wasn’t. The sole purpose of my quest has been pleasure — my pleasure.

The three restaurants that comprise my shortlist — which are regularly hailed as the three greatest on earth — are all, by definition, busy. They are booked solidly, and most would-be diners complain that it is impossible to get a table.

It isn’t. I pulled no strings to eat anywhere. None of them knew I would be writing about them. If you like what you read about them, and you want to eat there, you can. All you need is determination — and a little ingenuity — to get a reservation.

I began my quest at the Fat Duck, in Bray, Berkshire, which this year was voted by Restaurant magazine as the greatest restaurant on the planet. I followed up at El Bulli, where the Spanish magician Ferran Adria, regularly hailed by his peers as the greatest chef alive, performs alchemy on his ingredients. I concluded last month at the French Laundry in California. Both Heston Blumenthal at the Fat Duck and Adria are proponents of what has come to be labelled “molecular gastronomy”, which applies the principles of chemistry and physics to cooking, stripping away tradition and preconceptions and experimenting in a laboratory rather than a kitchen to see what works.

It’s easy to satirise such cooking, and in the hands of second order chefs it can be truly disgusting. The case for the prosecution: brussels sprouts soufflé in a whisky jelly (I kid you not). But in the hands of a master, the altered perceptions can be not only revelatory but joyous. One of Blumenthal’s classics, for instance, Sardine on Toast Sorbet, Ballotine of Mackerel “Invertebrate”, Marinated Daikon may sound bizarre, but as soon as you eat it you realise how limited we are to think of sorbet and sardines but never to put them together.

For all Blumenthal’s skill, the home of such cooking is El Bulli, on the Costa Brava. So legendary is it now — it opens for just half the year, with no more than 50 covers — that it has to turn away 400,000 requests for a table every year. I had been trying for five years to get a reservation. Clearly the food gods knew that this was the year of my quest, as my pleading e-mail was picked at random for a table in April.

I have already described the experience in its full glory to Times2 readers, so I will limit myself here to saying that El Bulli is far, far more than the showcase for a series of lab experiments. The ambience is one of total comfort, without the reverential — and off-putting — hush that some ostensibly great restaurants seem to encourage. The Spanish enjoy their food, and they take that enjoyment into even the most rarified of restaurants. Adria is able to redefine what it means to be a chef, and to take his profession in new directions, only because he is already so technically accomplished. I suspect that some “great” chefs would struggle to cook a bare omelette. Adria’s would be perfection.

If told I had to erase all memories of either the Fat Duck or El Bulli, I would struggle to decide which to lose. It’s difficult to judge the food on its own; as with any meal, the context is also pivotal. I went to the Fat Duck for my 40th birthday and to El Bulli after five years of trying.

In the end, the difference seemed that El Bulli deliberately serves its food as experiments in progress, while the Fat Duck approaches the same end — reinvention — with the determination that only dishes that have already been proved to succeed can be served. As to which is better — so what? I care even less now because, glorious as they both are, I realised from my very first mouthful at the French Laundry that I had found perfection. Indeed, I had an inkling even before I entered the building. Yountville, in the Napa Valley, is not merely picture-postcard pretty; it lives and breathes. The streets are spotless. Everyone smiles. The scenery — vineyards on rolling hills — is majestic. And, best of all, the residents, and the town, are real.

So the French Laundry has an immediate advantage; it is impossible to be in Yountville and not feel relaxed and happy.

But what matters is the food. Thomas Keller, the chef at the French Laundry, works very differently from Blumenthal and Adria. He grows and rears as much of his produce as possible, and aims at the most simple perfection — presenting ingredients in the best possible light. Interesting and unusual combinations, yes, but all designed to bring out the heart of flavours.

I had the nine-course tasting menu. Every course was a highlight, the menu perfectly balanced to mix the rich with the delicate, the piquant with the smooth. Sautéed Fillet of Chehalis River Sturgeon, with Marinated Sweet 100 Tomatoes, French Laundry Garden Tomato “Marmelade”, Fleur de Courgette Croquante and Yellow Squash Emulsion typified what makes the French Laundry the finest restaurant on earth: the best possible ingredients, cooked only to show off their quality, rather than the chef’s invention.

Desserts are, for me, usually a depressing indication that a good meal is ending, not least because I do not have a sweet tooth. But the Mango Sorbet, Yuzu-Scented “Genoise”, Goma “Nougatine” and Black Sesame “Coulis” would itself have changed my mind, so heavenly was the sorbet, if it had not been followed by a chocolate mousse and vanilla ice-cream (to reduce so sophisticated a dish to banality), which has stopped me eating chocolate or ice-cream since. I know already that I will never eat its like again, and cannot see the point of eating anything lesser. I lied slightly in my first sentence. My quest is far from over. I am not going to stop searching for the best food and the best chefs. But the quest has changed. Until the French Laundry, I had eaten meals which would live with me for ever and which I knew were near-perfect. But I always had the thought that somewhere out there was the mythical absolutely perfect. At the French Laundry, I realised for the first time that it is no myth. It exists. Now I know what perfection tastes — and looks — like.

So now I have a real yardstick for comparison. And that, I think, makes my quest even more intense.