When to say when

Some weeks after Christmas a huge parcel arrived containing a very large panettone - an Italian fruit cake, light saffron yellow and delicious. I am very partial to it. Indeed, I can remember the very first panettone I ate, at a cafe on the Piazza del Duomo in Milan in 1939. It had been offered me by my uncle. I liked the panettone, I liked my uncle, and this wouldn't be a story if the panettone that arrived nearly 60 years later had not been four kilos in weight - and were it not that this is not a cake on which to gorge yourself: it is rather to be eaten a little at a time - to my mind, at breakfast.

But receiving it did bring to mind one essential kind of food: the small and perfect. This is not mentioned much: we retain an atavistic fear of being without food, so that plenty always seems more vital than paucity.

Yet when you think about it, I think you will agree that two fresh, perfectly boiled eggs, with toasted "soldiers" nicely buttered, are not necessarily better than one such. In like fashion I can easily have my fill of Belgian chocolate, beluga caviar, Sydney oysters and smoked salmon. Big does not mean good. If it did, America would be a paradise of fruit and vegetables rather than the nightmare it is.

Of course, you can help yourself to just as much of anything as you want. The problem lies with others. My son-in-law, remitting the panettone as a sort of tribute, was being kind in the extreme. He knew I liked it, so he was donating not just a panettone, but the panettone of panettones, one fit for heroes. It is not unlike that old quandary the host finds himself in whenever he offers up a dinner: how much are his guests likely to eat?

Here, I must say, I vastly prefer generosity to the parsimony of certain (aristocratic) French houses I have eaten in. When madame says she herself eats like a bird, you know you're in trouble. Few things are worse than rising unsated from the table. On the other hand I hate waste, and dislike having to repeat the same meal for several nights just in order to finish up the leftovers.

Fortunately, the lore of eating has a sort of numerical guide to quantity and size. One boiled egg is equivalent to half-a-dozen oysters; two match a dozen. Up to six dates are the sign of a civilised eater; beyond that there are only gluttons. Steak is graduated: an entrecote is less than a sirloin, which is less than a T-bone, which is a long way from being a pave de boeuf. As to chicken, a breast is fine; to eat that and a leg, or a leg and a thigh, is carrying things too far, just as a single wing would be too little. One perfect peach is just that, as is one pear. A cluster of grapes will do, as will no more purple figs than fit into a small basket. A lamb chop may be single or double, but not triple. Sole is not eaten in pairs.

Thus has tradition created a sense of harmony and proportion. Part of my objection to the now-ubiquitous menu gastronomique (designed to showcase the chef's inventiveness) is that it exceeds the proper number of courses: even at an extravaganza, these should not exceed five. At least, not unless you prefer a display of prowess to good taste and satisfaction.

Yet a sense lingers that my son-in-law knew what he was doing, for if I say "freshly baked bread", we all know how tempting that is, and how hard it is to stop eating it while it is still warm. Or, to come a long way down the gastronomical ladder, how unavoidable is excess in nuts - even, God save us, in popcorn at the cinema.

At least if you overdo the popcorn and peanuts you have only yourself to blame. The restaurant equivalent - places which pride themselves on hearty fare - is less pardonable. I don't want to face a plate so heaped up that I cannot cut my meat without spilling food all over the table. The too-large portion is simply display; when a waitress asks me if I want a doggy bag, it's also waste.

No, fortunately, between the parsimony of perfection - the one splendid egg - and dread excess, there is the middle ground of sufficiency. But one man's sufficiency is another's blowout. Therefore, I should offer guests a little more than I would be smart to eat. At the very least, a guest should always be asked if he or she fancies a bit more. Giving just the right amount is to say that as a host, you know how much your guests ought to eat, which is presumption. And that is probably why guests are not invited to eat just one boiled egg