As far as I know, I have no gastronomic nemesis. I’m ambivalent about okra; no matter how meltingly cooked, I can taste only soggy string. I wouldn’t knowingly order a brace of sheep’s eyeballs, either, but I did manage to chew on stewed chicken feet at a wedding banquet.

Other people, though, boast an impressive catalogue of culinary no-nos that would be consumed only under threat of starvation. Here is a selection from the Times office: Brussels sprouts, cauliflower, beetroot, liver, peanut butter and meringues (I wish I could cultivate that one). And even then, starvation seems the more attractive option. “I would rather die than eat liver,” is the instinctive reaction of my occasional office neighbour, Ann Treneman. Raw tomatoes and garlic score surprisingly highly on the yuk index, too.

Such dislikes are not always rooted in fussiness. They can be anchored strongly in biology. A quarter of the population are “supertasters” ? they have more tastebuds on the tongue than other people. They can be identified using a chemical called 6--propylthiouracil (prop for short), which has a bitter taste. The supertasters can’t stand it, the “medium tasters” (50 per cent) can detect it but find it bearable, and the “non-tasters” (25 per cent) don’t notice it at all.

The supertasters tend to have stronger food dislikes ? scientists think of them as inhabiting a different world of taste from the non-tasters. Prof. Linda Bartoshuk, the Yale University academic who coined the term supertaster, has compared the “pastel world” of the non-taster with the “neon-lit” world of the supertaster. The supertaster’s palate is a strong physiological relic of an evolutionary distaste for bitter foods ? people learnt to associate bitter tastes with poisons, and thus developed an aversion to such tastes.

Women are more likely than men to be supertasters. Studies suggest that this choosy subset, who are less keen than the general population on sweet, fatty tastes, have a lower body mass index than non-tasters, whose undiscerning palates lead them to ingest more calories on average. Unfortunately, a survey at Rutgers University, New Jersey, suggests that supertasters also consume low amounts of the bitter-tasting vegetables ? broccoli, Brussels sprouts ? that are so good for health, although this has yet to be confirmed in a large study.

Many of the liver-loathers ? and here they join forces with the meringue-hater ? cite texture as the off-putting factor. Food scientists point out that 75 per cent of the nerves emanating from the fungiform papillae (the small bumps on the tongue that house tastebuds) are linked to pain and touch centres in the brain. This also explains why some people reject spicy foods and fizzy drinks: they feel the “burn” more intensely.

However, while you might inherit the tongue structure of a supertaster, biology does not wholly determine food preferences. Conditioning also contributes ? and it appears to start from the moment that an infant suckles, because flavours are transmitted through breast milk. One study showed that babies whose lactating mothers drank carrot juice were more accepting of carrot-flavoured baby rice during weaning. Breast-fed infants are more likely than formula-fed babies to try a vegetable the first time it is presented. The mothers of nine-year-old children are less likely to describe their progeny as picky eaters if those children have been breast-fed.

Dr Gillian Harris, consultant clinical psychologist at the Children’s Hospital in Birmingham, says that infants between the ages of four months and a year are, nutritionally speaking, blank slates upon which food preferences can be imprinted.

“Preference is a function of exposure,” Harris says. “You should be feeding your baby at four months mashed or pureed versions of whatever you would like them to be eating at two years old. They get used to the taste, the look and the smell. The later you leave it, the more difficult it is.”

Research suggests that the neophobic response ? an aversion to the unfamiliar ? strengthens with age. Between four and seven months of age, many babies will happily eat a foodstuff after only one encounter. Two-year-olds, in contrast, require about ten exposures, and 4 to 5-year-olds may need 15 introductions.

Harris, who runs a feeding clinic for children at the hospital and is also a senior lecturer at Birmingham University, believes that almost anyone can be tutored to eat any food if he or she really wants to. In such cases, the food aversion can be “cured” just like any other fear, by gradually introducing and increasing exposure to the detested foodstuff.

Among the children she sees at her clinic, scrambled egg is a commonly feared food because of its slimy, lumpy texture. She urges sympathy for these children, who are genuinely phobic about putting such foods into their mouths. Carbohydrates such as crisps and bread rarely present a problem, implying that a fear of slimy foods can result from a hardwired instinct to not want to eat something potentially dangerous. The colour, smell or texture triggers a deep-seated neurological klaxon.

“Scrambled eggs, sauces with bits in and liver have a ‘double texture’,” Harris explains. “Children can develop a disgust response, which amounts to ‘this is dirty or contaminated or dead’ and so they can’t eat it. This is an evolutionary response ? the brain says ‘don’t eat this because it’s not safe’.”

She accepts that some supertasters may never be able to stomach liver or scrambled egg. “There may be some people who will never eat certain foods because the sensation of eating them ? the taste, the smell ? is too extreme.”

As well as biology and conditioning, psychology may have a role to play. There is preliminary evidence that implanting false memories about certain foods can discourage some people from eating them.

Prof. Elizabeth Loftus, from the University of California, Irvine, convinced some students that as children they had become sick after eating hard-boiled eggs or pickle. She asked the students to fill in a food history questionnaire, then gave them back their results with a falsehood inserted. A quarter of the students swallowed the lie and said that they were less likely to eat those foods again.

Loftus, who published her results in Social Cognition, concludes that “food is a surprisingly easy target for memory manipulation”. The drawback is that it worked for items such as pickle and asparagus, but not for chocolate or crisps.

In addition, the idea of implanting false memories to keep people thin ? without their knowledge ? is likely to make ethicists choke on their Scotch eggs.

THE TIMES, LONDON