# Fasting and toxins -- scientific evidence? **URL:** \ **Category:** Factual Questions\ **Created:** [September 19, 2005, 12:00pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345 "2005-09-19T12:00:12Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![ratatoskK](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ratatoskk/32/2987_2.png) [@ratatoskK](https://boards.straightdope.com/u/ratatoskK)\ **Post date:** [September 19, 2005, 12:00pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/1 "2005-09-19T12:00:12Z")
Last night I had dinner with a group of friends. Two of them had recently gone on a one-week fast for the purpose of ridding their bodies of “toxins.” My question is, what (if any) is the scientific evidence for this? I’m not asking for anecdotes of how much better you feel – I’ve heard many of them and don’t doubt that. Also I’m not looking for comments about whether this is a good or bad way to lose weight, clear your head, etc. I specifically want to know about fasting and clearing yourself of toxins. I tried googling and got lots of health-food-related sites but could not find anything scientific. I also searched Medline and Mecscape, and there are a lot of hits on “fasting” (re: glucose, etc.) but I couldn’t find what I was looking for. These friends of mine claim that you have to fast for 3 days or more, because after the third day the “toxins” start to “come to the surface” and “leave your body.” Since we were having a nice meal, I didn’t ask them for citations. The closest thing I found to a scientific comment on this subject was [Go Ask Alice](http://www.goaskalice.columbia.edu/2221.html) , but I am interested in more detailed information (but not so jargon-laden that I can’t understand it). I also searched the Dope but didn’t find what I’m looking for. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [September 19, 2005, 12:04pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/2 "2005-09-19T12:04:53Z")
Any actual toxins are eliminated by the kidneys as part of normal metabolism (not counting food that is indigestible and passes through the digestive system). Next time, ask your friends exactly what toxins they’re talking about. Odds are, they won’t have any idea. ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [September 19, 2005, 3:56pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/3 "2005-09-19T15:56:03Z")
Tell them that ear candling is a much more efficient way to remove toxins from your body… 😉 ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [September 19, 2005, 4:08pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/4 "2005-09-19T16:08:30Z")
> [@RealityChuck](#): > > Any actual toxins are eliminated by the kidneys as part of normal metabolism (not counting food that is indigestible and passes through the digestive system). As I understand things, the liver also plays a significant role in removing and/or processing toxins. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [September 19, 2005, 4:49pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/5 "2005-09-19T16:49:14Z")
Don’t some toxins (like some heavy metals - mercury specifically) “sweat out” without being processed by the kidneys? ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [September 19, 2005, 5:02pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/6 "2005-09-19T17:02:33Z")
Usual disclaimer, I’m not a doctor, nutritionist, or biologist… As we all know from the fine, fine medical documentary series, “House”, it is possible for certain fat soluble toxins to bioaccumulate and then be released once the body begins fasting. Chlorinated compunds used in pesticides are a good example. This may not actually be a good thing, as the toxins may start doing damage once released into the body. But nonetheless, I can see how fasting could potentially remove toxins from the body. (Although one web site I quickly scanned suggests a high protein, low sugar diet to accomplish the same thing, supplemented with vitamins of various sorts.) So it’s not inherently bullshit, although in practise I’d guess it’s unnecessary, ineffective, or actively dangerous, depending on what toxins we’re talking about. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [September 19, 2005, 6:45pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/7 "2005-09-19T18:45:52Z")
> [@Finagle](#): > > Usual disclaimer, I’m not a doctor, nutritionist, or biologist… > As we all know from the fine, fine medical documentary series, “House”, it is possible for certain fat soluble toxins to bioaccumulate and then be released once the body begins fasting. Chlorinated compunds used in pesticides are a good example. This may not actually be a good thing, as the toxins may start doing damage once released into the body. But nonetheless, I can see how fasting could potentially remove toxins from the body. (Although one web site I quickly scanned suggests a high protein, low sugar diet to accomplish the same thing, supplemented with vitamins of various sorts.) > > So it’s not inherently bullshit, although in practise I’d guess it’s unnecessary, ineffective, or actively dangerous, depending on what toxins we’re talking about. My micropreemie daughter’s neonatologist told me a similar thing, and used it as rationalle for me to carefully not lose any weight while pumping breastmilk for her until she reached her due date. He said her preemie body might not be able to withstand the toxins that would be released from fat stores and find their way into the breast milk. Once she reached full term and her health became more stable, it was considered safer to begin losing weight. (Yeah, now if I could only \*do \*that!) ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [September 19, 2005, 9:38pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/8 "2005-09-19T21:38:32Z")
The idea that “toxins” are being stored up in the body due to modern life-styles, and which can be “flushed” or “cleansed” away, is the basis of a vast number of quack cures, including a myriad of supplements, colon and liver “cleanses”, massage therapy, removal of amalgam fillings etc. etc. As others have noted, your body does a fine job of breaking down and eliminating toxins (the term covers a variety of naturally occurring waste products that are toxic only in large concentrations). If you’re exposed to non-natural environmental toxins, it’s going to take a lot more than a quack cleansing regimen to eliminate them. **Jackmannii** , M.D. ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [September 19, 2005, 10:00pm UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/9 "2005-09-19T22:00:16Z")
Just a question: How much did they have to pay to do what amounted to not eating, since the guys who recommend things like fasting to remove toxins don’t do “free.” ---
**Author:** ![Chairman\_Pow](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Chairman\_Pow](https://boards.straightdope.com/u/Chairman_Pow)\ **Post date:** [September 21, 2005, 4:27am UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/10 "2005-09-21T04:27:42Z")
Wait. If the toxins are stored in fat cells and fat cells are best gotten rid of by fasting (among other things), wouldn’t the fast therefore be a good method of getting rid of the toxin-carrying fast?\* Now a week-long fast obviously isn’t going to do the trick, but aren’t we theoretically on the right track? - Cite: > [@Art Devany](#): > > So, what do you do to get rid of those fat cells who won’t give up their contents to other cells and who refuse to die? > > You have to starve them, but not by starving your other organs. You must change the allocation of resources away from fat and to the other organs and muscle. You must empty the muscle of its glycogen stores so that muscle cells become highly sensitive to insulin, in spite of the attempts of fat cells to deter this. Aerobics won’t be enough because 1. if you are obese you are probably made “lazy” by that very fat you are trying to lose, 2. you will not drain enough glycogen, and 3. you will not sufficiently alter the hormone profile to redirect nutrients away from fat. You have got to do glycogen-draining anaerobic exercise. And, you have to eat less, but intermittently as in every other day eating. This begins to attack those fat cells in a way against which they cannot effectively defend themselves. From [here](http://www.arthurdevany.com/archives/evolutionary_fitness/index.html#a000213). ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [September 21, 2005, 6:32am UTC](https://boards.straightdope.com/t/fasting-and-toxins-scientific-evidence/322345/11 "2005-09-21T06:32:58Z")
I actually heard a seminar today where a professor was studying an ABC-transporter (these sit across your cell membranes and pump things in and out) that was present only in bone marrow stem cells and red blood cells. It turns out that this transporter was very important in exporting toxins out of the stem cells to help them survive your entire lifetime. Two of the toxins discovered to be exported were 1. some sort of product that is the breakdown of chlorophyll, found in all the plants you eat. It was similar in structure to some molecule your cells used so could be mis-incorporated 2. a toxin found in over-cooked meat…2-amino-something-or-other He also noted that this transporter was inhibited by Prilosec and other medications…so be careful not to eat too many vegetables or burnt meat when on these might be the moral here 🙂