Scientists Explain Why People Still Have Room for Dessert Even When They're Full
Mon, November 29, 2021

Scientists Explain Why People Still Have Room for Dessert Even When They're Full

Desserts always appear irrisistable, that no one could ever resist its charms and taste, of course / Photo Credit via Pxfuel


For many, feeling stuffed is not an excuse to not have dessert. One can bet that there will be people who will always have room for dessert—even if they have to loosen their belt. Why is that?

Well, experts believe it's because of the existence of the so-called "dessert stomach." They claim that not only is a dessert stomach real, but it is also part of human evolution.

The appeal of food

Experts said the dessert stomach is because of a mechanism called sensory-specific satiety. It's when the more a person eats something, the more they grow tired of it, leading to the sensation of fullness.

However, when given a new taste or texture, they will likely find room to accommodate the new flavor. Penn State University professor Barbara Rolls said the decline in pleasure from food is specific to the food a person has been eating or of a similar kind.

"So, while you might lose your appetite for that food, different food will still be appealing. That's why you always have room for dessert," added Rolls, who has been studying this area for 40 years.

Food becomes less tasty and less appealing in terms of look, smell, and feel as a meal progresses, the Daily Mail reports, noting that this drives people to try something different.

It adds that the sensory-specific satiety mechanism evolved to keep people healthy, in which they will likely get all the nutrients they need by limiting the appetite for one food and encouraging humans to switch to another.


Dessertas can be both delicious and fascinating, but, not all individuals are priviledged to eat as much as they want / Photo Credit: Dave Dugdale via Flickr


There has been longstanding evidence for the sensory-specific satiety mechanism, found in a 1939 Chicago study of newly-weaned babies who were given 33 different types of food. The babies chose the food they wanted to eat and for a short period, some of them fixated on a certain dish.

However, the youngsters still ate a well-balanced, varied diet over time. According to the Daily Mail, this led researcher Clara Davis to conclude that "some innate automatic mechanism" may have guided the children in choosing the food they want to eat—and it seems that sensory-specific satiety is that mechanism.

Testing the phenomenon

Based on Rolls' earlier studies, news website Vox conducted an experiment to summarize the phenomenon of people feeling full but still having the appetite for another food.

In the experiment, the researchers gave volunteers a large serving of macaroni cheese and instructed them to eat as much as they can until they feel full. Afterwards, they were given another serving as a "dessert."

The volunteers were then asked to rate their interest in the meal on a scale of one to 10. Results show the participants' interest rate fell from 6.2 out of 10 to merely 1.3 after the first meal.

The researchers also measured the amount of macaroni cheese the participants ate, and they found that the volunteers managed just one ounce for "dessert." By the time they finished eating, their interest in the pasta plummeted further to 0.2 out of 10.

Yahoo! News says the experiment was repeated but instead of pasta, the volunteers were given ice cream for dessert. Their interest in ice cream remained high throughout the meal—having eaten three times more of the pudding than the pasta "dessert."

"[Sensory-specific satiety] encourages you to switch from food to food, so it’s a good thing," Rolls told Vox. "We’re omnivores and we need to eat a variety, so having a shift in how much we like the food that we’re eating but still like other foods encourages variety."


Bad news for dieters

Thanks to the sensory-specific satiety mechanism, humans can get all the nutrients they need to maintain a healthy body. For some people, however, this mechanism may not be as helpful for their bodily function.

One of Rolls' study showed that people are likely to eat 60% more calories than they need if they have a meal of four different courses instead of just one in which all dishes are the same.

"If we are presented with a variety of food, surrounded by a variety of food, it encourages us to keep eating beyond usual satiety," the professor said.

It could also be because of how some types of food are designed to be tempting. According to Tera Fazzino and Kaitlyn Rohde, researchers from the University of Kansas, these foods fall into three categories:

• Fat and sodium - which have more than 25% of total calories from fat at least 0.30% sodium per gram per serving.
• Fat and simple sugars - foods that have more than 20% total calories from fat and more than 20% from simple sugars.
• Carbohydrates and sodium - foods that have over 40% total calories from carbohydrates and at least 0.20% sodium per gram per serving.



Fazzino and Rohde, who conducted a study to define what are hyper-palatable foods, state that their findings may be used in several ways if scientific evidence to support their definition accumulates and shows that it is linked to overeating and obesity-related outcomes.