# Do "negative calories" really exist?

**URL:** <https://boards.straightdope.com/t/do-negative-calories-really-exist/157265>\
**Category:** Factual Questions\
**Created:** [February 24, 2003, 10:34pm UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265 "2003-02-24T22:34:40Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Short\_Guy](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Short\_Guy](https://boards.straightdope.com/u/Short_Guy)\
**Post date:** [February 24, 2003, 10:34pm UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/1 "2003-02-24T22:34:40Z")

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I read this once in a “little known facts” e-mail (I know, not the best source of reliable information:rolleyes: ). Is there really such a thing as ‘negative calories’? In other words, is it true that digesting celery for example takes more calories than the body can get out of the celery? If so, is there any other ‘food’ that does this?

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**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\
**Post date:** [February 24, 2003, 10:47pm UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/2 "2003-02-24T22:47:42Z")

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This was discussed [here](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=136271), [here](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=12690) and [here](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=4112).

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**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\
**Post date:** [February 25, 2003, 3:55am UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/3 "2003-02-25T03:55:10Z")

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I think digesting sawdust would probably use more calories than it provides. And you would also get that full feeling and be less hungry at mealtime 🙂

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**Author:** ![BuckleberryFerry](https://avatars.discourse-cdn.com/v4/letter/b/5f9b8f/32.png) [@BuckleberryFerry](https://boards.straightdope.com/u/BuckleberryFerry)\
**Post date:** [February 25, 2003, 3:59am UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/4 "2003-02-25T03:59:49Z")

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A perfect first post, **Still Cooking** , and welcome!

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**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\
**Post date:** [February 25, 2003, 4:10am UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/5 "2003-02-25T04:10:37Z")

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Raw potatoes will lose you more calories than you gain. You could eat raw potatoes till you’re stuffed day in and day out but you’d eventually starve to death (of course a raw potato only diet probably has a few other issues that would bother you along the way).

Cooked potatoes are another matter. Cooking breaks they very long carbohydrate molecules in potatoes for you so your body has less work to do upon digestion and will see a net gain for eating them.

This isn’t to say eating raw potatoes is harmful. Just don’t eat them to the exclusion of everything else.

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**Author:** ![Short\_Guy](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@Short\_Guy](https://boards.straightdope.com/u/Short_Guy)\
**Post date:** [February 25, 2003, 3:54pm UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/6 "2003-02-25T15:54:15Z")

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Thanks, \*\* DarrenS \*\*. I had done a search, but clearly I didn’t look hard enough.

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**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\
**Post date:** [February 25, 2003, 4:19pm UTC](https://boards.straightdope.com/t/do-negative-calories-really-exist/157265/7 "2003-02-25T16:19:17Z")

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I remember from a TV program about survival in the wilderness that you should avoid mushrooms, even if you know that they are edible, on the grounds that there is so little nutrition in them that you will spend more calories looking for them than you will gain from eating them.

I have never liked mushrooms anyway. 😉