Hate on a plate

Food aversions can be real, though some may be just in your head

George H.W. Bush in 1925. He later complained that his mother made him eat broccoli, which he came to detest.
UC Irvine's Elizabeth Loftus has shown that food aversions can be falsely planted in people's minds.
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I do not like broccoli. I haven't liked it since I was a little kid and my mother made me eat it. I'm president of the United States, and I'm not going to eat any more broccoli.

— George H.W. Bush in 1990


— Elizabeth Loftus, professor of psychology, UC Irvine, earlier this year

The 41st president is hardly alone. For all of the well-documented healthfulness of broccoli, the idea of eating it turns some people a shade of green.

But then, when it comes to food, everybody hates something.

In a 2007 study published in the Journal of Psychology, researchers at Saint Mary's College of California and Kansas State University reported that people seem to put their disliked foods into three basic categories: vegetables, meat and fat.

Texture, too, plays a role. “We noted in our study that unfamiliar textures such as soggy bread or oysters and clams were more likely to be aversive to (study participants) than firmer textures such as steak or apples,” said Christina L. Scott, a professor of psychology at Saint Mary's, in Moraga.

“Anyone who has ever discovered their PB&J sandwich has gotten wet in their lunch bag can tell you how unappealing soggy bread can be.”

Whether it's soggy bread or worse, food aversions are both natural and unnatural, intuitive and learned. And sometimes, says Elizabeth Loftus, a psychologist at the University of California Irvine who studies the formation and consequences of false memories, food aversions can be figments of a misinformed imagination.

Like all animals, humans are hard-wired to seek out some foods and avoid others. We instinctively recognize certain foods – such as rotting fruit, poisonous mushrooms and tainted meat – to be at least potentially harmful.

We innately prefer foods that are sweet, which not only indicates something edible, but also that the food contains sugars and other carbohydrates, necessary to health and survival, albeit within certain limits.

Conversely, bitterness is frequently a sign of toxicity, and the human mouth is finely tuned to detect it. Our tongues possess just a few types of taste receptors keyed to sweetness, but at least five dozen that target bitterness.

Ironically, some foods like broccoli are bitter because they contain astringent compounds intended to deter vegetation-munching insects. To bugs, the compounds are toxic. To humans, they're anti-carcinogenic – a big reason why eating broccoli is good for you.

If many food aversions are instinctive, many more seem to be learned, usually quite early in life, sometimes before birth. In one study, women who drank carrot juice daily in the late stages of their pregnancies had babies who, at six months, liked carrot-flavored cereal significantly more than did babies whose mothers had not consumed carrot juice.

And scientists say breast-fed infants appear to eat a wider range of foods as they grow older than formula-fed babies because, it's presumed, they wereexposed to more tastes through their mothers' milk.

Food dislikes form most readily in the first seven years of life. These aversions also tend to be the strongest and most persistent. In youth, our ability to taste and smell are most acute. (Flavor is a blend of taste and smell. The latter sense begins to decline at age 30. By 80, people can typically detect only one-fourth of the flavors they could as children.)

So it's not surprising that children are sometimes put off by foods that, in adulthood, they will find pleasing – or at least inoffensive. Pregnant women also possess a heightened food sense, a precaution against eating something that might harm their unborn child. That's why expecting women may be extraordinarily picky eaters, concluded Cornell University scientists in a 2000 study. It's a big reason for morning sickness.

“Nausea and vomiting in pregnancy is not a sickness in the pathological sense,” said Paul Sherman, a professor of neurobiology and co-author of the study. “We should change (morning sickness) to wellness insurance.”

Mostly, though, food aversions are the consequence of social interaction and personal experience. Dr. Alan Hirsch, a psychiatrist and founder of the Smell & Taste Treatment and Research Foundation in Chicago, said cultural biases teach us that some foods are disgusting and inedible.

“We don't eat snake or dog in the United States, but they are commonly consumed elsewhere. Drinking milk in Japan isn't seen as appealing. We have psychological prohibitions against some foods regardless of how they taste.”

Children commonly acquire long-lasting food aversions from their parents. “A child who watches her father avoid vegetables each night at the dinner table will mostly likely model the same behavior,” said Scott at Saint Mary's College. “A child who grows up in a family of vegetable eaters, who has repeated opportunity to eat them, is more likely to do so – and learn to enjoy them.”

Other food aversions are the product of conscious choice, said Scott, “because we anticipate an outcome.” Avoiding certain foods while dieting is an obvious example.

Gender preferences play a role. “Most 'light foods' like salads, yogurt and fruit are considered more feminine,” Scott said, “while heavy, smelly foods like pot roast, herring, corned beef and cabbage are seen as masculine.” Chicken and oranges, on the other hand, are considered to be gender-neutral.

Some food aversions (or preferences) are the product of social class or self-image. Scott said sweet alcoholic drinks are broadly perceived to be lower-class or more juvenile than beverages like straight scotch or bourbon.

Food for thought

Clearly, most food aversions are psychological. They're linked to negative past events or bad memories. “If you had a special meal with a spouse who you later divorced,” said Hirsch, “you might avoid eating that food later because it reminded you of him or her.”

Or it can be a case of what psychologists call classical conditioning, said Scott. A baby fed overheated strained carrots may unconsciously associate the food with a burned tongue and reject them in the future. “It's not the carrots that are aversive, but the temperature.”

Sometimes, though, a food aversion isn't real; a person only thinks he hates a certain food.

Loftus, the psychology professor at UC Irvine, has spent years studying and documenting the phenomenon of false memories – seemingly real recollections of events that never actually happened. Most of her work has dealt with issues related to abuse and trauma.

In 2005 she began a series of studies to investigate whether false memories could result in lasting behavioral or attitudinal changes. She decided to use food as her investigative tool.

In her first experiment, she asked test subjects to fill out extensive questionnaires that probed their likes, dislikes and food history. Each participant subsequently received a highly touted “computer profile” that described, among other things, a gastronomical mishap early in their lives.

Half of the participants were told they had once gotten sick eating a hard-boiled egg; the others were told it was a bad pickle. In neither case did the event actually happen. And yet, in subsequent questioning, the participants expressed aversions to either hard-boiled eggs or pickles.

Later experiments induced test subjects to report unfounded dislikes of egg salad sandwiches, strawberry ice cream and peach yogurt. Conversely, one study showed participants who were told they had enjoyed asparagus as a child rating the vegetable more highly than control subjects did.

The phony aversions weren't temporary, either, Loftus said. Participants still disliked targeted foods months after their testing, though the aversion faded when participants were eventually informed it was based on an implanted false memory.

There were a few foods, though, that Loftus and her colleagues could not persuade test subjects to dislike – in particular potato chips and chocolate chip cookies.

“In a real food aversion, if you get sick eating something novel, a single bad experience may be enough to put you off it forever,” said Loftus. “But that doesn't seem to happen with things you eat everyday, especially fattening foods like potato chips.”

It's possible to overcome real food aversions. “You can learn to overcome and even like what is an innate aversion,” said Hirsch. “Take capsaicin, the chemical that makes chile peppers so hot. It's an irritant. It burns taste buds. That's pain you feel when you eat peppers.”

Children typically don't like chile peppers, even in cultures that eat a lot of them, he said. They develop a liking because it's elemental to their culinary experience, because everybody else is eating them.

The same can be said of coffee. “Black coffee is bitter, but people overcome this aversion because it's a customary social lubricant,” said Hirsch. “They doctor it with sugar and cream. It also helps that there's a pharmacological factor: The caffeine wakes people up.”

Unlearning a food aversion requires a combination of repeated exposure and reinforcement. A person needs to eat a lot of the disliked food and somehow come to enjoy the experience.

That means one thing, said Scott: “You need to be motivated. Unless someone actively wants to override a food aversion, it is unlikely to occur.”

So maybe Loftus is wrong. When it comes to liking broccoli, the first President Bush may be a lost cause. Indeed, after publicly disparaging the vegetable, an annoyed Bush subsequently told farmers to stop sending him samples.

“Now look,” he said, “this is the last statement I'm going to have on broccoli. There are truckloads of broccoli at this very minute descending on Washington. My family is divided. For the broccoli vote out there: Barbara loves broccoli. She has tried to make me eat it. She eats it all the time herself. So she can go out and meet the caravan of broccoli that's coming in.”

The 41st president is going to stick with what he likes.

His favorite food: pork rinds.