Always going back for a second piece of birthday cake? Can't resist that second handful of M&M's?
You probably already know you have a weakness for sweets—but we're here to tell you it's not your fault. According to a new study, your sweet tooth might not be caused by a lack of willpower, but rather a literal weakness in your ability to taste sugar.
The Monell Chemical Senses Center and the QIMR Berghofer Research Institute tested 243 pairs of identical twins, 452 pairs of fraternal twins, and 511 unpaired individuals. They all tasted and then rated the intensity of two natural (fructose and glucose) and two articifial (aspartame and neohesperidine dihydrochalcone) sugars. The researchers chose to study different types of twins because identical twins share nearly identical genes, while fraternal twins share about half—thereby helping the researchers determine how shared genetics influence perception of just how sweet something tastes.
Their findings suggest that genes might account for up to 30 percent of how well (or how poorly) you can taste sugar.
"Eating too much sugar is often seen as a personal weakness. However, our work suggests that part of what determines our perception of sweetness is inborn in our genetic makeup," said study author Danielle Reed, Ph.D., a behavioral geneticist at Monell, in a release. "Just as people born with a poor sense of hearing may need to turn up the volume to hear the radio, people born with weak sweet taste may need an extra teaspoon of sugar in their coffee to get the same sweet punch."
So if someone calls you out on your sweet tooth, feel free to mention this study.