This came up in a conversation about weird ways to loose weight. So how many calories would be lost with the average pint of blood?
no clue, but i’d have to add that obviously you’d also burn calories by replenishing your blood.
er,
My WAG is a whole lot. I must sleep for 12 hours everytime I give blood. I get so damn tired.
When you lose your red blood cells, you’ve lost some capacity for transferring oxygen, which is required for burning fat. So I think there’s a possibility of actually storing some fat from food after donating blood.
Nooooooo! Tell me it ain’t so? That’s so unfair. :mad:
About six hundred.
What about apheresis?
How did they get the 600 cal figure?
When I was in high school, one of the guys on the wrestling team was trying to make weight for a meet that night. Somebody told him he could get the weight off by serial masturbation. He was about half way to his desired weight when he was discovered hard at work in the locker room. It took about 12 minutes for the entire student body to hear about the situation. Moral: he shoulda given blood.
Heh, we have regular blood drives at work and I’m always telling folks to sign up for the weight loss aspect. Now I’ve got an actual figure to throw at them, how nifty!
'Course, I’ve been regularly donating for years and am still…voluptuous, so I dunno how much convincing I can really accomplish, but it’s still cool. 
I know this wrestler…
I’d argue that the amount of caloric loss from blood donation would be minimal - and might conceivably be negative. Blood is not a very metabolically active tissue. There are many reasons why donation might make you feel tired (especially if you have a low hematocrit to begin with) but it isn’t fatigue due to metabolic effort. In fact, the loss of blood slightly decreases the oxygen available for high metabolic effort, and may decrease overall metabolism slightly in many other ways.
A person like Harmonix, who sleeps 12 hours after a donation (and probably feel less energetic for longer) might actually conserve more calories by resting than they burn replenishing heir blood. And that’s not counting the Red Cross cookies and juice.
About half the blood volume is Red Blood Cells; most of the rest is serum (leaving at most a few percent for other cells) However RBCs aren’t really living cells. They have no nucleus: it is shed before they enter the blood stream as reticulocytes, an immature circulating form that “ages” [the way wood or wine ages, not the way living cells do) to mature RBCs over the next 4 days. Without a nucleus, they can’t produce the enzymes for biochemical processes, or produce structural proteins to maintain themselves – a pre-RBC cell burns calories; a mature RBC doesn’t. For their entire 100-120 day “mature lives”, RBCs are inert sacks of protoplasm, getting progressively more battered/tattered until they break up. Much like me.
When you donate blood, the volume is immediately replaced by water (and other plasma components you already had stored up). A fairly small amount of biochemically active immature red blood cells are recruited early from the bone marrow, but RBC production is a weeks-long production line. The body just pulls a few off the line early, and doesn’t even ramping up production very much. By the time the increased production reached the bloodstream, things would have largely evened out on their own anyway: all the cells that were already in production at the time of donation would have reached the blood, and the cells which were already circulating last longer when there are fewer cells in circulation, so you’d be back to normal anyway.
Those are just a few of the reasons why your metabolic expenditure might not increase, and might decrease slightly. Frankly, even if the 600 calorie figure of that tongue-in-cheek letter to the editor were accurate, it’d be diddly-squat (a few granola bars, as he noted) after you subtract the cookie and juice they give you. You might think “a unit of blood contains 600 calories, which must be replaced”, but the recovery is more an equilibration than a tit-for-tat replacement (e.g. old RBCs surviving longer, rather than more new RBCs being produced)
Having said that, I am a big fan of donating blood. It makes me feel great. I tend to be more active than I would otherwise be for the next couple of days, so I for one, might lose some weight in the long run.
Ok, so I (normally) undergo apheresis every two weeks. They take 510 mls of plasma. Since they take ‘no’ red blood cells, would I be burning calories replacing everything else?