March 20, 2012 -- Is the secret to a slimmer waistline found in your nose?

A new study suggests that food aromas can make a difference in the amount of food people eat.

Dutch researchers found that a food's aroma intensity influenced a person's first bite as well as additional bites. Higher aroma intensities, or more concentrated smells, led to smaller bite sizes of a food. (A bite size in this study referred to the amount of food placed in the mouth at any one time.)

"The reduction in bite size as a result of aroma is relatively small," the researchers write. In fact, they estimate it may be between 5% and 10% of food intake per bite.

People typically take smaller bites of a food when they don't like it or it's unfamiliar, as well as when they're feeling full. Bite size can also vary based on a food's texture.

For this small study, published online in the journal Flavour, researchers wanted to find out how increasing the aroma intensity of a food affected the amount eaten on a bite-by-bite basis.

They watched 10 people, aged 26 to 50, eat a vanilla custard dessert. Instead of handing volunteers a spoon and having them sit at a table, each participant was seated in a dentist's chair.

They were fitted with a nose piece connected to a device that delivered smells of the creamy dessert. And a tube was place into their mouth to pump in a desired amount of custard.

While this may not sound like a great way to enjoy a sweet treat, it allowed the scientists to vary a food's aroma as well as measure how much was eaten.
Stronger Smells, Smaller Bites

Participants pushed a button to control the amount of the custard dessert fed into their mouths while their noses were catching a whiff of one of three creamy aroma conditions. They were randomly presented with no smell, a weak smell, or a strong creamy smell; however, the taste of the custard remained the same throughout the test.

Researchers found that increasing the aroma intensity reduced the bite size. In other words, stronger smells led to smaller bites.

"Bite size was associated with the aroma presented for that bite and also for subsequent bites (especially for the second to last bite)," says Rene de Wijk, PhD, at the Top Institute of Food and Nutrition and Wageningen University in the Netherlands, in a news release.

"Smaller bites are associated with lower flavor sensations from that food, and there is an unconscious feedback loop using bite size to regulate the amount of flavor experienced," de Wijk says.

For example, if a person smells a strong creamy aroma, it may make the custard seem thicker and creamier, and possibly higher in fat and calories, so they may eat less of it.