Calories are a unit of energy, not weight. Conflating the two is sloppy thinking. Eat nothing but grass and you will die of starvation. Yet ruminants live on g

Calories are a unit of energy, not weight. Conflating the two is sloppy thinking. Eat nothing but grass and you will die of starvation. Yet ruminants live on grass, and its energy content can be measured with a calorimeter. Thermodynamics are a poor mechanism for understanding biology.