cr: Andrew Johnson via Unsplash

In a study out of Yale this week, researchers explored the neurological pathways governing a fly’s choice in what to eat—is it the taste or the calories they’re after?

To explore this, scientists laced a normally sweet, nutritious food with bitter quinine, and watched the flies brains as they decided whether to eat that, or another food that was sweeter, but lower in calories.

In the end, it mattered how hungry they were. If the flies were hungry, they chose the bitter food with more calories, but if they were satiated they chose the sweetness, suggesting even in a fly there are multiple pathways governing these decisions—the gut’s needs can override the brains dopaminergic reward system.

While it’s not mentioned in the study, I can’t help but think this is the answer to the mystery of why artificial sweeteners don’t help people lose weight. Diet soda satisfies the reward system with a hit of sweetness, but does nothing for the body’s deeper craving for calories. So we drink diet soda, then eat more, and it makes no difference to calorie intake.

This doesn’t mean we aren’t better off drinking diet soda, as simple sugars are inflammatory at these high doses, and lead to diabetes and other health problems—and are kind of the opposite of chemotherapy, when you think about it, feeding tumor growth. But don’t expect to lose weight.

fruit flies
descending
on fallen fruit