Crave sweets? Well, stop blaming your sweet tooth. Researchers have found that mice prefer sugary water even if they lack a gene needed to taste it. Although the mice could not taste sweets, reward centres in the brain reacted when the mice drank water spiked with sucrose, but not when they drank water mixed with a low-calorie artificial sweetener. The results, published this week in Neuron 1, suggest that mice can detect calories without relying on their taste buds — a finding that could change our understanding of the sugar cravings that can plague dieters and contribute to obesity.
The presence of a calorie-sensing pathway makes evolutionary sense, says study author Ivan de Araujo, now at Yale University in New Haven, Connecticut. “The taste system evolved to allow animals to quickly detect what is worth eating versus what is not,” says de Araujo. “But the real reward that they need is not the taste itself but the calories.”