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NEW YORK (Reuters Health) - People who are overweight may be able to shed pounds by sprinkling special seasonings and sweeteners on the food they eat. These "tastants" stimulate the sense of smell and taste, making people feel fuller faster and helping them to eat less, a study found.
"This approach uses natural physiology to help people lose weight, which is different than other approaches," Dr. Alan Hirsch explained. "We know that diets don't work because people do not have the will power to succeed. Instead of looking at the front end - how people eat - we looked at the back end, how can people feel full faster?"
As founder and neurologic director of the Smell & Taste Treatment and Research Foundation in Chicago, Hirsch observed that after people lost their sense of smell and taste from head trauma, they would gain 10 or 20 pounds.
This led him to test whether heightening the sense of smell and taste would help people lose weight. "It makes anatomic sense because there is a direct relation between the olfactory bulb at the top of the nose and the brain's satiety (fullness) center," Hirsh explained at the Endocrine Society's annual meeting underway in San Francisco.
In a study lasting 6 months, Hirsch and colleagues had 2,436 overweight or obese adults sprinkle a variety of calorie-free "tastant" crystals on the food they ate. They put the salt-free savory flavors -- like cheddar cheese, onion, and ranch dressing -- on salty foods and put sugar-free sweet crystal flavors -- like cocoa, spearmint, banana, strawberry and malt -- on sweet or neutral-tasting foods.
A control group of 100 volunteers used non-flavored "placebo" crystals. Both groups were told not to change their eating or exercise patterns.
A total of 1436 subjects with an average initial weight of 208 pounds completed the study. According to Hirsch, their average weight loss over a 6 month period was a little over 30 pounds or about 15% of their body weight versus 2 pounds in the control group.
There are a whole host of reasons why tastants would work, Hirsch said, "but the best hypothesis is that these powerful smells and tastes acted to enhance sensory-specific satiety." They send messages to the brain that say "I'm full."
The tastants also fuel "the phenomenon where the first bite of the food tastes great, but the last bite doesn't taste so good," he explained.
"So, for instance, if I order pizza, the pizza box smells so good when it first comes in, and then after I eat it the first thing I want to do is get rid of the pizza box because the smell that was pleasant before has become unpleasant," Hirsch added. "When you cook spaghetti all day long, at the end of the day, you don't feel like eating spaghetti, because you've smelled it all day long."
"It's the same thing here. By having people sprinkle these flavors on the food it changed the nature of the food so that they eat it, it tastes good, but they get full faster," Hirsch said.