WIKIMEDIA, TIIA MONTOScientists have engineered fruit flies that can’t taste sugar, and, at first, the insects will show no preference between sugar water and plain water. But after 15 hours without food, the flies start to choose the sugar water, seemingly sensing the fact that the liquid contains life-sustaining calories even though they can’t taste anything.
“They sense calories in a way that is somehow independent of tasting the calorie itself,” said Ivan de Araujo, a neurobiologist at Yale University.
The experiment described above, published in the Proceedings of the National Academy of Sciences in 2011, is just one example of several recent studies that have found that mice, rats, and fruit flies have sensors, separate from taste buds, to detect nutrients. It’s not just a matter of feeling full, said de Araujo. That is, the animals don’t appear to be reacting to the stomach stretching, the release of hormones such as insulin, and other negative satiety signals that tell animals to stop eating when they’ve had enough. Rather, the signals that de Araujo and others in his field are studying ...
