Let’s say you are dying of starvation. You pull one of your teeth out, causing blood to slowly seep into your mouth, which you swallow. The calories from the blood getting digested will delay the time you die of starvation, right? Or will losing blood while starving kill you faster?
Takes nutrients to both digest things and make more blood and you won’t be able to use all of it the second time around so no you’d be netting negative calories.