That's correct, but we're pretty efficient - from 75 to 99%. This is typically around 90% except for fiber, which is marked down in calorie labels already. It a

That's correct, but we're pretty efficient - from 75 to 99%. This is typically around 90% except for fiber, which is marked down in calorie labels already. It also depends on what exactly you're doing with the energy, if you're in a calorie surplus then protein to tryglyceride metabolism is less efficient than, say, dietary fat to tryglyceride, but this can just be neglected. But yeah, human digestion is pretty efficient. Muscles are far less efficient though, around 30%, which is a neat fact.