# When you give or lose blood do you lose calories? **URL:** \ **Category:** Factual Questions\ **Created:** [November 14, 2001, 11:39pm UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416 "2001-11-14T23:39:57Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![JungleLove](https://avatars.discourse-cdn.com/v4/letter/j/839c29/32.png) [@JungleLove](https://boards.straightdope.com/u/JungleLove)\ **Post date:** [November 14, 2001, 11:39pm UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/1 "2001-11-14T23:39:57Z")
I know this question will strike many as stupid, but I have wondered about it. When you give or lose blood do you lose calories? ---
**Author:** ![Bob\_Scene](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@Bob\_Scene](https://boards.straightdope.com/u/Bob_Scene)\ **Post date:** [November 14, 2001, 11:48pm UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/2 "2001-11-14T23:48:58Z")
I don’t think it’s a stupid question. Yes, you lose calories. Blood contains fat, protein and sugar, all of which represent calories. Your body will have to use some calories to replace it. I don’t have a number handy (or feel like calculating one), but the number of calories in a pint of blood is probably insignificant. I say that because blood is mostly water and the solid content of a pint of blood weighs much less than a pound. ---
**Author:** ![Keeve](https://avatars.discourse-cdn.com/v4/letter/k/f07891/32.png) [@Keeve](https://boards.straightdope.com/u/Keeve)\ **Post date:** [November 14, 2001, 11:58pm UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/3 "2001-11-14T23:58:45Z")
> [@](#): > > The average person stores 1500 to 2000 calories of energy as blood glucose and glycogen, That’s from [http://kevingong.com/Health/glycogen.html](http://kevingong.com/Health/glycogen.html), on the first page when I gave Google “calories in blood”. I forget how much blood is in the body, but whatever fraction one pint is of that, multiply that by 1500-2000, and there’s yer answer. ---
**Author:** ![GilaB](https://avatars.discourse-cdn.com/v4/letter/g/8e7dd6/32.png) [@GilaB](https://boards.straightdope.com/u/GilaB)\ **Post date:** [November 15, 2001, 12:52am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/4 "2001-11-15T00:52:42Z")
I don’t have a cite, but I believe that one pint of blood costs your body about 1,000 calories to replace. ---
**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\ **Post date:** [November 15, 2001, 2:29am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/5 "2001-11-15T02:29:26Z")
We had a similar thread [here](http://boards.straightdope.com/sdmb/showthread.php?threadid=76804) and I mentioned how one of my colleagues was about to publish “the” answer: **600 calories**. Unfortunately, I can’t get a link to full text of **Transfusion Medicine** , but the title of his short study is found on that journal’s web page, [here](http://www.blackwell-synergy.com/Journals/toc.asp?IssueID=7330). And, the title says it all. Look down about 3/4 of the page to p.390 ---
**Author:** ![JungleLove](https://avatars.discourse-cdn.com/v4/letter/j/839c29/32.png) [@JungleLove](https://boards.straightdope.com/u/JungleLove)\ **Post date:** [November 15, 2001, 2:40am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/6 "2001-11-15T02:40:24Z")
Want to say I did look in the Archives before I posted. I searched with- blood \ weight. I guess I should have searched with calories. Didn’t see that thread. I’ll check it out. Thanks. ---
**Author:** ![KarlGrenze](https://avatars.discourse-cdn.com/v4/letter/k/dbc845/32.png) [@KarlGrenze](https://boards.straightdope.com/u/KarlGrenze)\ **Post date:** [November 15, 2001, 3:01am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/7 "2001-11-15T03:01:26Z")
Erm…when you give plasma, do you lose the same, more, or less calories than when giving blood? I know I end up hungry after I give, but then by the time I’m finished giving it is usually my lunch or supper hour, so its not weird. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [November 15, 2001, 3:10am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/8 "2001-11-15T03:10:31Z")
> [@](#): > > \*Originally posted by Keeve \* > \*\* > > > [@](#): > > > > The average person stores 1500 to 2000 calories of energy as blood glucose and glycogen, > > That’s from [http://kevingong.com/Health/glycogen.html](http://kevingong.com/Health/glycogen.html), on the first page when I gave Google “calories in blood”. > > I forget how much blood is in the body, but whatever fraction one pint is of that, multiply that by 1500-2000, and there’s yer answer. \*\* You’re overlooking that glycogen is not stored in the blood, but in the muscles and liver. The adjective “blood” does not modify “glycogen.” Actually, it is superfluous and would have been better to have omitted “blood.” The cite is also defective in that neither glucose or glycogen is “energy,” but the fuel by which energy is produced through the chemical breakdown of ATP (chemical energy is changed to motor energy). ATP,therefore, stores the energy, not glucose or glycogen. ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [November 15, 2001, 3:12am UTC](https://boards.straightdope.com/t/when-you-give-or-lose-blood-do-you-lose-calories/93416/9 "2001-11-15T03:12:55Z")
Having now checked your link, it says that “blood glucose” contains 80 calories.