The holiday bulge is one part of Christmas nobody looks forward to. But in the future, avoiding it may be as simple as following your nose.
Scientists at an independent food-research firm in the Netherlands say they can help create food and drink with aromas that fool your body into thinking you're full.
Researcher Rianne Ruijschop and her team have found a way to enhance the familiar aromas in food enough to activate areas of the brain related to a full-stomach feeling.
A recent article in the Journal of Agricultural and Food Chemistry, a publication of the American Chemical Society, described the phenomenon in scientific prose like this: "Although the extent of retronasal aroma released appears to be subject-specific, food product properties can be tailored in such a way that these can lead to a higher quality and/or quantity of retronasal aroma stimulation. This in turn provokes enhanced feelings of satiation and ultimately may contribute to a decrease in food intake."
In other words: The nose knows.
The scientists were even able to get the nose to react to a drink much as it does to solid food and "significantly" increase the person's feeling of fullness.
"To our knowledge, this is the first time that such a result has been observed," scientists behind the study wrote.
Imagine going through a whole holiday season of parties, gatherings, noisemakers and balloons without ballooning up yourself. The secret is in making you feel full long before you have eaten too much; consuming manipulated food can release more aromas to fool your brain rather than fill out your waist.
There has been research focused on quenching hunger stimuli through ways other than eating, but they have focused mainly on the stomach and what happens after food is eaten, rather than on the process of eating itself.
Ms. Ruijschop is project manager for health and safety at Nizo, a company whose business is the development of innovative food techniques for the marketplace.
Ms. Ruijschop told The Washington Times by telephone that the method her team invented involves changing the structure of the food product only slightly "to make sure the right flavor is released at the right time."
"You could make a liquid more viscous or make a cookie more chewable," she said.
It's done "without adding anything artificial," she noted. "It's all about flavor release. We are able to increase or change the quality. You just choose another type of natural ingredient -- but not a chemical. The aim is to have a long, natural flavor release to have an accelerated rate of fullness."
Chewing and eating satisfaction, although it occurs in the mouth, depends much on nasal processes. This is why the sense of taste suffers when someone has a head cold.
In one part of the study, Ms. Ruijschop wrote, "Custard products with the addition of maltol or animalic" -- organic compounds related to aroma stimulus -- "were able to increase subjects' feeling of fullness significantly."
The added ingredient, or flavor component, is subtle, she emphasized, so a person would not notice any appreciable difference in taste.
Her study cited the common-sense fact that solid foods are more filling than liquids, and attributed that in part to solid foods' more-complex aromas.
As a practical application, she cited the example of yogurt, saying the fermenting conditions could be changed to make the texture thicker, releasing more complex aromas, and the taste would not be affected.
Another example, she said, involves the familiar smell of strawberries.
"If you add a natural strawberry aroma, you probably have a more complex aroma and feel more satiated," she said.
Trials to date only have been done on a limited scale, and longer trials are planned.
Her team's work does not represent a solution to the problem of obesity, she cautioned, but might help people "who eat too much and too often."
Natural ingredients such as fiber added for health reasons also can create fullness, as can less beneficial ingredients full of carbohydrates or saturated fat, found in a lot of processed food, John Finley, a professor of food science at Louisiana State University, said in an interview.
The fullness factor doesn't always stop people from eating too much, he said, since they may need the calories. Likewise, "It would be an oversimplification to say 'Because something smells good, I won't eat as much of it.' "
"What this research says is that a very complex set of aromas tends to be more satisfying," he added, citing the comparison of a fresh homemade meatloaf with a frozen meatloaf meant for the microwave.
The homemade version "brings out a lot of volatile characteristics" -- the kind that creates good aromas.
"The next step is to understand more details; to see how a fully developed meal impacts your total sensory experience, and see if it does actually have an effect," he added.
Mr. Finley said the research reflects a common-sense view that the feelings of satisfaction can be produced by sensory stimuli that don't involve actually eating food.
"You need to look at the visual effects as well," he said. "Go to a nice French restaurant, and you typically get a presentation of delicious-looking food that is like a bouquet. They [chefs] work really hard balancing aroma and flavor to get a great experience. You get this, and you don't have to eat as many calories."