Poor Gwyneth. Her latest cookbook, It’s All Good, won’t hit bookshelves till next week, yet critics are already lambasting her gluten-free, sugar-free directives. Sure, her recipes and penchant for dietary “cleansing” may be controversial from a health standpoint; one reviewer even called them creepy. But perhaps one group of people might benefit from them: foodies. Turns out, taking periodic breaks from a rich diet can prevent a palate from getting bored, or even worse, spoiled.
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In animal studies, rodents fed a high-sugar or a high-fat diet typically experience an increase in the hormone leptin; and, in turn, leptin has been associated with a decreased sensitivity to sweetness. In other words, the animals became less capable of detecting lower concentrations of sugar, explains Rocky Parker, Ph.D., a post-doctoral fellow at Monell Chemical Senses Center, in Philadelphia. Worse, the high-fat-fed rats not only grew obese, they had fewer sweet receptors—suggesting that leptin can possibly wreak havoc on the sweet receptor genes. And since sweet and umami taste share a common gene (Tas1r3), it’s also possible that leptin can affect nuances in the taste of umami as well.
Humans are not rodents, of course, but such research suggests that, over time, if we wine and dine too much, we could very well be missing out from a gastronomical standpoint: a pricey farmer’s market bell pepper may no longer taste as sweet; a gorgeous mushroom tart, no longer as savory.
Overzealous diners lose out in the short term too. “If you eat a lot of something,” says Guy Hartman, director of the creative and applications groups at International Flavors & Fragrances, North America, “your taste buds get fatigued by it. ”
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In addition, food experiences involve the brain as much as the tongue. Substituting an indulge-as-you-wish policy with an indulge-occasionally one will “change your neural circuits,” points out Nina Smiley, Ph.D., who leads a mindful-eating workshop in Mohonk Mountain House, in New Paltz, N.Y. What’s more, neurons emit dopamine, a neurotransmitter that signals pleasure. When you come across something associated with pure bliss — particularly if you’ve been missing it for awhile — dopamine will spike, explains Gene-Jack Wang, M.D., a scientist at Brookhaven Laboratories, in Upton, N.Y. So absence, in a biochemical sense, makes the brain grow fonder — including an absence of particular foods.
In a McGill University study, higher dopamine levels in fasting human subjects directly correlated with enhanced levels of pleasure from a post-fast meal. It’s unclear why. Subsequent research also suggests that increased levels of the hunger hormone ghrelin intensified not only the anticipation of something pleasurable, but also taste and olfactory perception, says Alain Dagher, M.D., associate professor of neurology at McGill University. The reason here is also unclear, but it makes sense from an evolutionary perspective: Hunger signals the brain to be more attentive — the more alert you are, the more successful your hunt for food, the greater the chance for survival.
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When New York City restaurant co-founder Dushan Zaric took a year-long alcohol break on the advice of his yoga instructor, he was hoping sobriety would improve his practice. That didn’t happen, he said, but he did notice a change in his palate. When he broke his fast with shot of tequila, he was “blown away.” “The flavors were so alive,” he recalls. Since then, he undergoes a three-week “cleanse” twice a year, swearing off liquor and certain foods. When he returns to his routine, he says, even miso soup can taste out of this world.
Moral of the story: Don’t follow restrictive diets to lose weight (or improve your yoga, for that matter). Try them to enhance your eating pleasure. And if you lose a few pounds along the way, that’s just icing on your now-much-tastier cake.