Now that you mention it, I'm pretty sure modern calorimeters won't catch the energy available via nuclear reactions. What if our digestive tracts have evolved

Now that you mention it, I'm pretty sure modern calorimeters won't catch the energy available via nuclear reactions. What if our digestive tracts have evolved some as-of-yet undiscovered mechanism to tap into that energy, thereby invalidating all the "CICO" people's claims? Now that would be a real pickle.