Anti-Hunger Smells Could Battle Obesity

Anti-hunger aromas that make one feel full could help fight the global obesity epidemic, scientists now suggest.

Everyone is familiar with scents that arouse the appetite, as well as odors that turn the stomach. But apparently molecules that make up a food's aroma can also activate areas of the brain that trigger the feeling of fullness.

As people chew food, scents wafting up to the back of the nose from inside the mouth help quench the sensation of hunger, food technologist Rianne Ruijschop at NIZO Food Research in Ede, The Netherlands, and her colleagues found.

"These were quite unexpected results," Ruijschop told LiveScience. "Everyone was quite astonished and very energetic about them."

Variety of findings

Certain aromas, flavors and textures were especially effective at making people feel full.

• Solid foods that required chewing and swallowing — thus offering a lingering release of aromas — proved more satiating than liquid foods.
• When odors linked either with fat, carbohydrates or proteins were tested, adding scents linked with carbohydrates or protein significantly increased the feeling of fullness, perhaps because they suggest food is high in energy.
• Complex aromas with multiple components were more filling than others with just one component. Complex aromas might tell the brain it's eating a variety of food and thus a large meal.
• The size of food samples had an impact, as smaller bite sizes prolonged the amount of time in which odors could have an effect.

In experiments, the researchers could modify how filling various foods were. For instance, making a beverage release aromas much like solid foods would significantly increased the feeling of fullness.

Feeling full

These findings could help researchers develop a new generation of foods that release aromas that help people feel full, therefore fighting overeating and obesity. Scientists might add capsules that boost or prolong aftertaste or release of aromas. They might also introduce chewy ingredients, or reduce bite size to increase the amount of chewing people have to do. Complex odors could be added, as well as scents that suggest the food is rich in energy.

In recent, as-yet unpublished work, Ruijschop said that by controlling aroma, they could in fact lower the amount of food people consumed by roughly 10 percent. They are now conducting long-term studies to see what effects months of changes in aromas can have on people.

Although aromas could contribute to the fight against obesity, "they're not really the solution by itself," Ruijschop noted. "It's also very much about changes in lifestyle."

Ruijschop and her colleagues detailed their findings in the November 11 issue of the Journal of Agricultural and Food Chemistry.

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