“uh, grass.”

come on now, let them cook, trust the process

Not dietal calories.

The calorie numbers we assign to food, measure how much energy our body extracts from them when eaten.

In this context, plutonium is closer to 0

If we instead want to measure the actual total physical energy content of materia, we would turn to E=mc^2, telling us that a gram of anything has about 20 million kcal, no matter if its plutonium or diet coke. which is a slightly less useful value on food labels :D