why do you lose calories when donating blood?
In: Biology
I’ve never heard someone phrase it that way. I supposed you’d lose some blood sugar, energy that’s in the blood, as they take blood out of you. I think the bigger consideration is you were effectively wounded. Your body now has lots of work to do to get back to normal. Work takes energy, energy comes from food. So eating after donating blood gives your body fuel to get to work. Water has to be moved, basically pumped, back into veins if you lost blood volume. Bone marrow needs to make new cells. If blood cells are the product, bone marrow is like the factory and food the fuel to fire up the factory.
Maybe the trick is blood sugar. When you lose blood more fluid gets moved into the veins, restoring your blood volume but reducing the concentration of nutrients. So eating then helps restore blood sugar and nutrient levels back up to normal.
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