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Dieting with flavor and taste — How flavors affect eating
The Hartford Courant
Ever witnessed this? Folks push away from the Thanksgiving table and protest that they can't eat another bite. A minute or two later, someone asks, "What's for dessert?"
David Katz uses this scene in explaining the principle behind his new diet plan.
We can max out on the flavors of a turkey dinner then crave something sweet — even if we've consumed more than enough food, he says.
In scientific circles, it's called "sensory-specific satiety."
Katz exploits this phenomenon to help individuals eat better and lose weight in his new book, "The Flavor Point Diet" (Rodale, 296 pages, $24.94), which he wrote with his wife, Catherine Katz.
Katz has a long list of credentials to lend credibility to his book: He's an internist and preventive-medicine specialist and co-founder and director of the Yale Prevention Research Center. He's also an associate professor of public health at Yale School of Medicine and a medical correspondent for ABC News. His press materials list him as a regular columnist for O: the Oprah Magazine and The New York Times Syndicate.
Katz's diet is not miraculous. It does not claim to harness some mysterious metabolic process that melts away fat. "Flavor Point" is a low-calorie diet. It provides about 1,500 calories of nutritious food a day, about 500 calories less than most average adults need to maintain their weight. That reduction in calories should result in gradual weight loss.
"The only way to lose weight is by taking in fewer calories," said Katz. "But can you cut calories without feeling hungry? The answer is yes."
Katz cites research that suggests that different basic food tastes stimulate different appetite centers in the brain. Eat something salty, and one part of the brain responds. Sour foods stimulate another appetite center and so on.
Once stimulated, these centers direct us to keep eating until they feel "full." Roast turkey might satisfy the "savory" taste center, but the aroma of pumpkin pie arouses the "sweet" appetite center, which then clamors for dessert.
Fast food and packaged snacks push all kinds of flavor buttons, some of them almost secretly. Katz observes that we might reach for our favorite breakfast cereal because it's sweet, not realizing it's also loaded with salt. Ditto for the salty corn crisps that are nearly as sweet as the cereal. We might not detect it, but our brains do. As a result, we tend to eat more of these foods.
No wonder nobody can eat just one.
"The food supply is booby-trapped to make portion control impossible," said Katz.
He defuses this dietary bomb by narrowing each day's flavor options and providing variety over time, not all in one mouthful.
The menu for each day of a six-week program centers on a specific taste theme. For example, there is "peach day," with a fresh peach on whole-grain cereal for breakfast, a peach jam (all-fruit) and peanut butter (natural) sandwich on whole-grain bread for lunch and peach-coriander turkey with oven-roasted potatoes and turnips for dinner. (The recipes are in the book.) There is also walnut day, tomato day, lemon day, bell-pepper day, thyme day and other flavor-theme days.
In theory, the narrowly focused flavors should mean that fewer of those appetite centers get triggered and that the dieter needs less food to feel full. Over time, flavor variety is increased somewhat, and ultimately, Katz intends for dieters to incorporate the flavor notion into their regimen.
Worth the inconvenience
In a 12-week trial among 20 employees and neighbors of Griffin Hospital in Derby, Conn., (where Katz also directs the Integrative Medicine Center), the average weight loss was 16 pounds. Participants lost as much as 8 percent of their body fat and as much as 7 inches off their waists, and they showed improvements in blood pressure, blood sugar and cholesterol.
The "Flavor Point Diet" is heavy on fresh fruits, vegetables, whole grains and lean poultry, as are most healthful diets.
But isn't adhering to flavor-theme days a lot of bother for busy Americans? Katz said that in the 12-week trial, the subjects reported that the first two weeks were a little tough. After that, they got into a groove, and many said they felt it was well worth the inconvenience.
"I think change is challenging," he said. "I think there is some work to be done here, and it's important to acknowledge that. If you want magic, go read 'Harry Potter,' I tell people."
Many years ago, scientists identified only four major taste categories: sweet, sour, salty and bitter. Now science tells us there are at least six distinct taste categories, the two additions being savory (also called umami) and astringent. Perhaps someday, we'll know of even more.
Our ability to appreciate the many subtle variations in the flavors of foods results from our perception of these categories of taste, combined with our interpretation of aromas.
Smell contributes a lot to our sense of taste, which is why eating with a stuffy nose tends to be so unsatisfying.
Although sensory-specific satiety drives us to prefer a variety of tastes, not all tastes are created equal. Sweet stimulates our appetites the most. This makes perfect sense. Breast milk is sweet.
In nature, sweet foods are scarce and include excellent sources of quick energy, such as ripe fruits and wild honey. Few toxic substances in nature taste sweet, so there are many good reasons for us to be born with a sweet tooth (or gums, as the case may be!).
Salt also stimulates appetite. Although humans aren't born with a predilection for salty food, we readily acquire it.
The same appears to be true for the savory quality of protein sources such as meat and cheese. In contrast, bitter and astringent tastes tend to suppress appetite, at least until we acquire a preference for them.
For example, coffee and beer are acquired tastes for many people, but once we learn to like them, we may like them quite a lot!
Reprinted with permission from
"The Flavor Point Diet" (Rodale)
Copyright © 2006 The Seattle Times Company