It was the cod liver oil that did it. Until that moment, my husband's keep-fit regime had been harmless - laudable, even. An unsatisfactory cholesterol test and an approaching 40th birthday had triggered a burst of health-conscious activity, and the results were good. After running and swimming every day for a year, his LDL count went down, and the 40th, though slightly nearer, seemed to hold fewer terrors.

Better still, he had been happy to leave me out of it. My cholesterol test came in near perfect, so, for a time, I was off the hook. He bought pill boxes marked with the days of the week, in which he deposited vitamin and mineral supplements the size of horse pills, and only once suggested that I take, as a precautionary minimum, a dose of selenium, vitamin E and aspirin every day.

I have never been keen on supplements: articles I read during the 80s, when power foods were big business, convinced me that most of them were a con, and the rest dangerous. I am a vitamin Luddite, staunchly old-fashioned in my view that if you need a boost of vitamin C, eat an orange.

For three days, I obediently took my medicine, but decided not to continue: taking pills makes me think I must be ill. I grew up with a clear idea of what constitutes a good diet, but my mother's notion of healthy eating involves a good deal of what you fancy. We didn't need to be told that red wine contains antioxidants before opening a bottle at dinnertime.

When my husband's parents gave us a juicer, I made strawberry smoothies; he made violent green drinks out of watercress and raw cabbage. It was I who instigated the switch from early-morning cup of tea to hot water with a slice of lemon, when I was pregnant, but he had to go one better, squeezing half a lemon into his cup - and no honey, either.

Before long, my husband was swimming a mile a day, running five. As his muscles became toned, mine flagged and flopped. His stomach flattened, mine bloomed. He was too tactful to mention it. But not all that tactful. "Your hair's falling out," he said casually one morning as he rinsed out the bath. "You need cod liver oil."

"Doesn't this stuff come in capsules?" I asked nervously, looking at the glinting yellow liquid in its medicinal-looking bottle. "Yes, but it's much cheaper like this."

Money has been a consideration throughout the one-sided fitness campaign. One afternoon he invited me out for a walk; instead of a romantic chat on a park bench, I found myself at the gym, signing for a year's membership - it was cheaper that way. I used to cycle to work until I lost my nerve after being knocked over once too often; since then I have talked about taking exercise, but never really intended to do anything. The gym - with all those much fitter people grunting and sweating, sizing up their muscle tone in the mirrors - was never in my plans. I didn't have the right attitude, or the right shoes. Yet here I was, economising, allegedly, by taking a year's membership: the more I worked out, the cheaper it would become. (I have actually been to the gym a couple of times now - and made it home without breaking into a sweat.)

Sometimes the path of dogged resistance does get lonely. With so much advice on health and fitness coming our way, perhaps it would be nice, just once in a while, to be able to say, "Yep, omega 3, I do that."

I put a spoonful of cod liver oil in my mouth. Oh, the horror of it. Greasy and nauseating, it was like kissing a fish. I danced round the kitchen, stuffing toast and peanut butter and bananas into my mouth, but couldn't get rid of the taste. All morning it came back to me in little fishy burps.

That's the end of my experiment with healthy natural remedies. Who needs hair anyway? I can always glue on extensions. He's welcome to his flaxseed oil, his free weights, his sweaty T-shirts. I'm having none of it.