Scientists discover why bread can cause weight gain without extra calories (opens in new tab)

Bread and other carbohydrate staples may be doing more than just filling plates—they could be quietly reshaping metabolism. In a surprising twist, researchers found that mice strongly preferred carbs like bread, rice, and wheat, abandoning their regular diet entirely. Even without eating more calories, they gained weight and body fat, not because they overate, but because their bodies burned less energy.