Have you ever eaten dessert despite already being full? It turns out that you are not the only one.
This phenomenon, called ¡°dessert stomach,¡± is extremely common among a wide range of animal species. Recently, scientists identified why it happens.
At the Max Planck Institute in Germany, neurobiologist Henning Fenselau and his team devised an ingenious experiment. They started by feeding regular meals to a group of mice, and after every meal, they gave the mice the option to eat a sugary snack. Interestingly, no matter how full the mice were, they never refused to consume their sweet dessert.
Curious about what was causing this strange behavior, the scientists decided to examine the mice¡¯s brains.
In mammal brains, there are special neurons that activate after you eat. These neurons, called the pro-opiomelanocortin (POMC)* neurons, send signals that tell your brain to stop ingesting any more food.
Surprisingly, these same neurons have a second function. They also signal the brain to release beta (¥â) endorphin,* a hormone that increases an animal¡¯s appetite for sugar. The result is that the rewarding feeling of eating sugar overpowers the feeling of being full.
Furthermore, Fenselau says there is an evolutionary reason that animals have developed ¡°dessert stomachs.¡±
¡°Sugar is rare in nature, but it provides quick energy,¡± he said. ¡°The brain is programmed to increase the intake of sugar whenever it is available.¡±
Thus, much like mice, we humans also have an ¡°extra stomach¡± for dessert. Throughout much of our species¡¯ history, obtaining energy from food was difficult.
So, whenever sugar was available, our brain encouraged us to take advantage of it, regardless of how full we were. And because our brains evolved to cope with these challenges, they often behave the same way today, even if food is readily available for many of us.