5

votes

Why is fructose avoided by so many?

Answered on August 19, 2014
Created May 07, 2013 at 4:57 PM

I have read that many people have to avoid fructose. What health conditions would make it necessary to avoid fructose?

I have also seen some people avoid fruit for weight loss. Has anyone on here dropped significant weight just from cutting out fruit? I personally find that I go through months where I can't get enough fruit and then months where I really have no desire to eat it. My weight (5'8 125) stays exactly the same though regardless of whether I eat 5+ pieces a day or none. I actually find that I have less desire to eat sweats when I do eat fruit since I satisfy my desire for sweats with mangos and pineapple.

Clearly, many people on here must have very different experiences with fruit than I do. I am just curious on others personal experiences with it as well as science behind why it is not optimal.

2edfcc5c8044bbb4f22ba6ea4289f592

(1398)

on May 21, 2013
at 08:17 PM

Fructose is converted to glycogen in the liver and stored only as liver glycogen. If liver glycogen stores are full it will be converted directly into glycerol, 3 fatty acids will be stuck on it, and it will be sent out into the bloodstream as a triglyceride.

Ed0cb30f40daff568778b776b2a5a81d

(943)

on May 21, 2013
at 09:19 AM

Can fructose only go into liver glycogen stores or can it also be used to refill muscle glycogen stores? Can you explain how glucose is metabolised?

3ce6a0d24be025e2f2af534545bdd1d7

(26217)

on May 09, 2013
at 01:32 PM

the "avoid fructose" crowd is usually geared towards those who are diabetic or severely over weight.

Ce41c230e8c2a4295db31aec3ef4b2ab

(32564)

on May 08, 2013
at 01:32 PM

Thanks, Stephen!

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on May 08, 2013
at 01:56 AM

I like your new pic Dragonfly, it looks good :)

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on May 08, 2013
at 01:38 AM

DR is skinny in spite of his diet. I mean, an anorexic who bikes as much as he does, no surprise he's underweight.

5e5ff249c9161b8cd96d7eff6043bc3a

(4713)

on May 07, 2013
at 09:19 PM

Also some pretty good research posted by Kresser not long ago that whole fruit consumption does not lead to T2D, IIRC.

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9 Answers

5
2edfcc5c8044bbb4f22ba6ea4289f592

(1398)

on May 07, 2013
at 07:26 PM

Frustose is metabolized differently by the body than glucose, the other main monosaccharide (sugar). Fructose goes straight to the liver to refill liver glycogen stores. If stores are full, it is converted into triglycerides (fat) and sent directly into the bloodstream. Chronic overconsumption of fructose is essentially toxic. The conversion of fructose to triglyceride causes large amounts of oxidative stress which over time can damage the liver. Not to mention high blood triglycerides are a major risk factor for heart disease. That all said, I think fruit can and should be a part of a healthy diet. Most people should limit fruit to 1 or 2 servings of low sugar fruits like berries or oranges. Some people will have to limit it almost entirely--diabetics and people with sugar addiction issues. Fruit has a moderate/low amount of fructose compared to HFCS, mainly because it is hard to consume comparable quantities of fruit. To reiterate something I think is important: I said Chronic Overconsumption. This is NOT 1-3 or even 5-6 peices of fruit a day. Chronic Overconsumption means 2 Big Gulps a day.

Ed0cb30f40daff568778b776b2a5a81d

(943)

on May 21, 2013
at 09:19 AM

Can fructose only go into liver glycogen stores or can it also be used to refill muscle glycogen stores? Can you explain how glucose is metabolised?

2edfcc5c8044bbb4f22ba6ea4289f592

(1398)

on May 21, 2013
at 08:17 PM

Fructose is converted to glycogen in the liver and stored only as liver glycogen. If liver glycogen stores are full it will be converted directly into glycerol, 3 fatty acids will be stuck on it, and it will be sent out into the bloodstream as a triglyceride.

3
0382fa263de4c83328dc34a56e25437f

on May 07, 2013
at 11:53 PM

I'm firmly in the seasonal-if-at-all camp, myself. I "cheat" with fruit a few times a year the way other people cheat with rice, chips, pizza, beer, ice cream, chocolate, whatever they consider cheating. Also, I find the longer I go without it (like, all winter) the less I want any when summer rolls around. Helped me drop weight and keep it off.

3
Ce41c230e8c2a4295db31aec3ef4b2ab

(32564)

on May 07, 2013
at 11:37 PM

Some of us are FODMAPS-intolerant. You can Google it!

Ce41c230e8c2a4295db31aec3ef4b2ab

(32564)

on May 08, 2013
at 01:32 PM

Thanks, Stephen!

Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on May 08, 2013
at 01:56 AM

I like your new pic Dragonfly, it looks good :)

3
Cb9a270955e2c277a02c4a4b5dad10b5

(10989)

on May 07, 2013
at 06:52 PM

Fructose is just the black sheep of the family. If anyone said they liked fructose, or that they wanted to bring fructose along everyone else would give them shit. I don't see a real problem with whole fruit, a little fructose here or there probably won't kill you and if it does, dibs on your computer.

DurianRider and Douglas Graham are pretty much Fruititarians just about, and they definitely are not overweight by any means. Are they dangerously underweight? I'll leave that for their doctors to decide.

The reason people avoid fructose though, besides the fact that it's a carb and some people here are on LC/VLC diets, is that studies on High Fructose Corn Syrup show that HFCS is very damaging to metabolic functioning basically. And very good at packing on the BF, I haven't seen any research that this translates to whole fruits though.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on May 08, 2013
at 01:38 AM

DR is skinny in spite of his diet. I mean, an anorexic who bikes as much as he does, no surprise he's underweight.

5e5ff249c9161b8cd96d7eff6043bc3a

(4713)

on May 07, 2013
at 09:19 PM

Also some pretty good research posted by Kresser not long ago that whole fruit consumption does not lead to T2D, IIRC.

1
D74288318247c62923457d39a068e3a7

(116)

on May 21, 2013
at 08:55 AM

Fructose is a more potent glycating agent than glucose, and is as much as 10-fold more efficient at forming AGE's. Fructose, compared with glucose or sucrose, accelerates the normal aging process.

https://www.youtube.com/watch?v=Jze6w06nLu4

http://jn.nutrition.org/content/128/9/1442.long

1
Medium avatar

(10611)

on May 08, 2013
at 12:46 AM

The best reason to avoid fructose (and any other simple sugar for that matter) is that if you don't metabolize it right away you store it. It digests and enters the bloodstream faster than fats and proteins. If you're sedentary most of the day it's not your friend.

1
242f56a9e5c9c24633b7a1a8177d27ff

on May 07, 2013
at 07:53 PM

http://www.youtube.com/watch?v=dBnniua6-oM

Check out Lustig for an in depth analysis. Worth pointing out that he is referring to the fructose in HFCS and sucrose (which are almost chemically identical), and not fruit (because it contains fibre), but most people trying to lose weight, or get rid of sugar addiction may be wise to avoid fruit as well.

1
D8104254471a3aabe86f20f5d0a9d584

on May 07, 2013
at 06:00 PM

I have completely dropped fruit from my diet as I found it put me on the same sweet roller coaster as sugar needing to eat most of the time and having sweet cravings which I no longer get. Fruit is sugar. Period. And the way in which is broken down in the body means it can only be stored as fat and not utilised for energy directly. This fat storage mechanism was useful for our ancestors who ate seasonally and required fat deposits for leaner winters however we are now faced with year round pineapple, mango and bananas which I believe has also contributed to obesity. Is fruit healthy? Im sure in moderation its fine. I choose to eat it seasonally and therefore its a rare treat. I believe this is how we evolved.

0
Medium avatar

on May 07, 2013
at 11:47 PM

HFCS f*** me up metabolically, from screwing with my leptin response to throwing my insulin into whacky, unnatural postures. Nothing wrong with fructose for 'healthy' people. Normal amounts of it, from normal, whole foods. At 255 lbs (5'7", female) it was a pretty vicious cycle until I got a hold of it. Now at 167lbs? I'm not anywhere near as damaged as before, but I'm still avoiding the fructose 'beast' because it slows my weight loss to 1 lb a week, despite eating at a pretty decent deficit.

I don't blame fructose for my not getting control of myself sooner. Or do I? Hmm.....

Also, I'm androgen-dominant. That's just my physiology, and it makes me insulin sensitive. Not all body types handle fructose the same way. Obviously you're fine.

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