Yeah I thought that would get your attention. I donate blood six times a year. Six pints, three quarts, 0.75 gallons. At 3500 calories/lb, about how much weight do I lose? Any metabolic costs in changing food or fat to blood? Neglect the weight of 3/4 gallon of blood, I’m interested in fat loss.
Also, at 230 lbs could I safely donate more than once every two months? We have a company blood drive every two months, which I believe is as often as some rule (or possibly law) will allow. I’m assuming I would have to go to some trouble to get special permission.
Thanks in advance for your response. I will be away from internet access until next Saturday.
I’d heard once that a pint of blood took about a thousand calories to replace, but don’t have any cite for that.
I doubt that they’d give you special permission to donate more than every eight weeks, since they’re very anal about abiding by all of the rules. Once, when my vein collapsed after they’d taken only a very small amount of blood, I was warned that I still couldn’t donate for another eight weeks.
Most of the weight you would lose from donating blood would be due to the weight of the blood itself, and so would be temporary. Remembering one litre of water weighs one kilogram, and the specific gravity of blood is 1.006 or so (equivalenmt to water for your purpose), you would lose a little more than a pound a pint.
Safety factors for medical procedures are not determined by how often YOU could give blood, which is certainly more than 6 times per year if you weigh 230. It is determined by how often well over 95% of average people can safely give blood. Bureaucracy being what it is, they would be unlikely to make an exception and it is probably not worthwhile to determine exactly how much YOU can give before you get anemic. This would depend, of course, on the quality of your bone marrow.
Thank you for taking the time to answer. This must sound like an odd way to diet, but I figure two or so pounds a year over the last five or six years is significant.
Society could use more blood donors. If weight loss is 2-3 pounds a year, this might convince more people to donate. I intend to follow up on this. The question may not be found using the standard calorimeter burn test. I also want to know if being temporarily anemic would slow down your metabolism to the point that fat loss would be affected.
A bunch of WAG’s, approximations, and assumptions:
albumin protein in 1000 cc of plasma = 40 gm = 160 calories
sugar in 1000 cc of plasma = 1 gm = 4 calories
fat in 1000 cc plasma = 1 gm = 9 calories
Total: 173 calories per 1000 cc plasma
protein (hemoglobin) in 1000 cc whole blood = 150 gm = 600 calories
Since a typical unit of blood contains about 400 cc, half of which is plasma, one unit contains (2/10 X 173 albumin, sugar, and fat calories) + (4/10 X 600 hemoglobin calories). This equals about 275 calories which is close to what the Red Cross claims.
After posting my response, I e-mailed a friend of mine who had once considered the issue of the number of calories in a blood donation. In fact, some time ago, he had submitted a short letter to a medical journal in which he proposed enticing blood donors by advising them that this was a quick way to lose (a bit of) weight (not to mention that they’d be doing a good deed).
Well, he tells me that his letter will be published in a forthcoming issue of Transfusion Medicine. In the letter, he calculates that one unit of donated blood is the equivalent of 600 ingested calories (or, as he puts it, three donuts).
By virtue of it being in print, this number may become the “official” answer to the OP.