Ambient temperature at thermoneutrality (30°C) suppresses hypothalamic and systemic metabolic changes induced by calorie restriction in female mice, whereas standard laboratory housing at 22°C induces cold stress that alters the metabolic response to calorie restriction.

When mice eat less food, their bodies try to save energy by lowering body temperature, but only if it is cold. In cold conditions, the brain uses a specific molecule to make a gas that opens blood vessels and lets heat escape, while also breaking down fat and muscle for fuel. In warm conditions, the same molecule goes to a different pathway that helps repair cells instead, so the body does not lower temperature or break down tissue as much.