"Why do we learn to like foods? When they're paired with something our brains are programmed to see as good," says Dr. Linda Bartoshuk of the University of Florida, a specialist in the genetics of human taste.

    Unfortunately, our brains are programmed to encourage us to enjoy tastes that are not good for our health: food that is fat (salt) and food that is sweet. The urge to consume fat is probably evolutionary and linked to survival. But what is necessary for survival isn't all the brain wants.

    University of Michigan researchers have found that eating something tasty can spark brain cells that sense actual pleasure to start firing rapidly. More thought provoking is how intensely people sense different flavors seems to affect how healthy they are.

    According to a recent University of Connecticut study people they label as  "supertasters," are those who don't like vegetables because they find them more bitter than the average person. Supertasters may be more at risk of developing colon cancer as a result.

    "People pile a lot of guilt on themselves," says Connecticut's Dr. Valerie Duffy, who is leading research into the links between inborn "preference palates" and health.

    "We know oral sensation varies," she adds. "Instead of making one dietary recommendation for all, can we individualize it for what people like to eat?"

    One in four people is what scientists call a supertaster, born with extra taste buds.

    They think some vegetables are very bitter, and hate the texture. They get more burn from chili peppers, and perceive more sweetness than other people. And they don't care for fat. They tend to be skinny because they're such picky eaters.

    Scientists came up with the name because these people show an extreme reaction when given a certain bitter chemical widely used in taste research -- a chemical that certain other people, dubbed nontasters, can't even detect.

    Those nontasters make up another quarter of the population. They like veggies, but unfortunately prefer heart-clogging fat, along with sweets and alcohol.

    Everybody else falls somewhere in-between.

    Fortunately, you can train your taste buds. The variety of foods you ate as a child, and the emotional connections to certain foods, are more important than biology in determining food preferences, Bartoshuk says.

    Pair a bite of sweet potatoes with the broccoli, and veggie-haters might find the greenery tastes OK after all, Duffy suggests. Or try caramelizing the leeks.

    Taste buds also dull with age -- so the Brussels sprouts you couldn't stand at 20, you may enjoy at 50.

    But taste starts before a food actually touches the tongue. Even more important than sniffing its aroma is chewing, which releases vapors up the back of the nose. You think you're tasting a flavor that really you're unconsciously smelling. It's called retronasal olfaction, and it sends flavor information along a different, more sensitive brain pathway than traditional sniffing does.

    The brain, meanwhile, is busy trying to regulate competing signals from stomach hormones that say "I'm full" with the yum factor.

    Michigan researchers recently implanted electrodes into the brains of rats to track a pleasure-sensing region called the ventral pallidum. That region's cells fired in a frenzy when the rats ate a flavor, sweet or salt, that they craved, but slowly stopped as the rats got tired of eating the same old thing.

    (Agencies)