FOR REASONS that you wouldn't thank me for explaining - especially if you're reading this over breakfast - the doctor recently told me to consume more fibre. I frankly didn't know what he meant. "Does that involve eating more fruit?" I said, hauling up my boxer shorts. (For the injunction to eat more fruit is, I usually find, the depressing punchline to any lecture on diet.)

"No," he said, and gave me a description of what fibre involves, which, for the benefit of anyone as ignorant as I am, I will sum up in the following word: Alpen. Alpen, it seems, contains every kind of fibre, including moral fibre.

Since seeing the doc, I have bought many boxes of Alpen. I'm actually rather good at buying Alpen; I find it very easy. The problem comes in eating the stuff, because I am not - when all is said and done - a rabbit.

I take the warning from the doctor seriously, though, especially since it comes in close conjunction with a spot of bother experienced recently by a builder friend of mine. He'd been to hospital for a check-up, and was given a warning about the level of cholesterol in his blood.

I tentatively wondered whether his cholesterol level was by any chance related to his consumption, every day at 11am, of eggs, chips, bacon, black pudding, sausage, fried bread and toast with extra butter.

"Could be," he mused. With my own new-found expertise I pleaded with him, at the very least, to incorporate beans into his breakfasts. "Because beans," I said, "contain fibre." "Oh, right," he replied vaguely.

I was raised by my father in the north of England, and healthy eating was no part of his culture. Consequently it was no part of mine.

I have never eaten a piece of fruit when a bar of chocolate was simultaneously available. I have never read an article about food - although I have spent quite a lot of time looking at pictures of Nigella Lawson - and the one recipe that I'm good at cooking is sausages in red wine, which begins: "Take one large lump of lard..."

But now, under the tutelage of my clued-up wife, I'm starting a new, sensible regime. Curry-wise, I am ratcheting down from my usual prawn vindaloo, which is categorised at my local takeaway as "hot," to prawn madras, which is categorised as "fairly hot".

The difference between "hot" and "fairly hot," I am excitedly discovering, is that whereas with the former you feel terrible for the whole of the next 24 hours, with the latter, you feel terrible only until about 3pm the next day. I have also found a fruit that I actually like, pomegranates, which are indecently close in taste to red wine.

In the back of my mind, though, is my image of my north of England grandfather. He cooked all his food in fat - the same fat, moreover: a greyish substance that he kept, and which he hardened in a cup between meals. I don't think I even saw him look at an apple. He died when he was 96.