Paleo Diet and Paleolithic Diet Questions & Answers

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I have no problem with the concept that excessive fructose intake is probably bad for you and that those with blood sugar problems need to avoid fructose, glucose, starch, etc. But is there any evidence that moderate fructose consumption by a healthy person in the form of whole foods is bad for their health? Should your kid be allowed to eat an apple or an orange at lunch and then later eat a banana? Or is this bad. What evidence do we have on this subject? After all, we do have a metabolic pathway to process fructose so it seems to me that we are designed to process fructose to some extent. Perhaps the problem occurs when that metabolic pathway is overwhelmed by excessive intake? (We are not talking about sodas and candybars here, just whole healthy food intake that also contains fructose).

{Note that this question is different than other similar because I am asking for specific EVIDENCE that MODERATE intake is bad for the HEALTHY. It's a specific set of parameters I am interested in.}

flag	asked Jan 16 2011 at 18:38 Eva 22.3k●4●24●71

We don't have evidence that it's good either.... – Stephen-Aegis Jan 16 2011 at 23:16

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Fruit has been consumed by men for millions of years. To change that you would need rock solid evidence of the supposed negative effects of fruit. Unlike the cases of grains or beans, there is no such negative evidence against fruit, then the reasonable thing to do, is to keep having fruit, based on personal preferences. – Philosopher Jan 17 2011 at 4:05

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Metabolic pathway thru the LIVER which filters TOXINs is a ba argument. We have a metabolic pathway for alcohol too, doesn't make it good. AGEs are still a side effect. There are essential proteins, essential fats but no essential carbs. That argument only works if our bodies clearly need it for something that we can't get elsewhere.(I apologize if this sound like an attack, it's. Devils advocate/love to actually learn why it's useful) – Stephen-Aegis Jan 17 2011 at 9:33

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Pets lower blood pressure, or so they say. Could be true the cat is secretly planning to assasinate me in my sleep. Prob is, he knows he doesn't yet know my PIN code to my bank account, so thus I am yet safe. For now. As for metabolic pathway through the liver, toxins are simply removed and excreted whereas fructose is utilized as fuel and to replenish glycogen. Big difference. Plus the human taste receptors are designed for us to seek sugar, not shun it. Most paleo sugar sources would have had fructose. It's obvious we are designed to want and use fructose. – Eva Jan 18 2011 at 6:55

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we are not designed... – Dan May 15 2011 at 22:55

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Heather · Accepted Answer · 2011-01-17 16:44:17Z UTC

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Check out Kurt Harris' new Jimmy Moore interview; he talks briefly about this, saying that HEALTHY humans are meant to be able to deal with a certain amount of fructose. He gives an off-hand amount of sugar that a healthy adult might be able to process per day, I think it was 50 g sucrose? He didn't provide references at the time, being a spoken interview, but maybe if you go over to his website and raise the question he or someone else who knows can elaborate.

answered Jan 17 2011 at 16:44

Heather
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Yup, like all toxins, healthy humans can handle it. Alcohol is a prime example of the exact same thing. In fact there are studies showing health benefits from moderate alcohol consumption compared to none or little. But theirs money in studying alcohol and no money studying fruit, hence our studies are limited – Stephen-Aegis Jan 17 2011 at 17:07

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The studies on alcohol are covered in a diff thread, but basically all I saw are epidemiological and possibly flawed. Anyway, there is no well known obvious benefit to alcohol metabolically. Whereas fructose provides an energy source and replenishes glycogen. Some can live on fruit for many a month and still feel good. If you are starving and near death, fruit can save your life. Alcohol won't. I am not saying eat only fruit, but alcohol is not closely comparable to fruit as to healthfulness. – Eva Jan 18 2011 at 7:01

Stephen-Aegis · Answer 2 · 2011-01-17 10:44:07Z UTC

Fruit stalls fatloss, we have tons of evidence, even on PH alone, we have N=1 over and over and over, people getting over loss when stopping fruit intake, and people stalling out by eating it. If 1 piece of fruit (arguably below defined moderate by most people) can take an otherwise great flowing plan and stall it out, theres more going on than simple glycogen restoration.

I lost the majority of my weight as Low Carb, restored my insulin sensitivity etc etc. my liver glycogen was CLEARLY not capped, yet fruit (or alcohol) stalled me out faster than anything. I add alcohol in there, because it seemed to have the same exact effect. When I ate 1 piece of fruit, my metabolism altered, my body stopped burning fat. If fructose is a healthy way to restore liver glycogen, why does that happen? Not N=1

When I ate 1 piece, my hunger cravings would go from none, Zero, to Raving Relentless Beast... I had to eat shortly afterwords... if nothing else is going on, why do my cravings for food suddenly skyrocket? Again, not N=1. Fructose has been shown to impede Insulin and Leptin, and not trigger Ghrelin... which explains this scientifically. Yes the intial testing may have been on HFCS, but the Empirical data with fruit definitely corroborates.

In a healthy individual, with a healthy liver, we can tolerate toxins. Tolerated is not Optimal. Regardless, our liver is required to process fruit. our body cannot process Fructose without it. and barring immediate storage after conversion... cannot use it. In addition, Advanced Glycation End Products(AGEs) are formed thru this conversion... these dont go away. These are known to at least contribute or be highly related to aging. If even minimal fructose is OPTIMAL, why would we produce a permanent TOXIN as a byproduct of storing? not N=1. The science supports this at any level of intake. The argument here is that AGEs happen from alot of other pathways as well(stress?). and small amounts of fructose produce small amounts of AGEs that may be very minimal in the big picture, and its the copious amounts eating by SAD that induce the (noticable)life shortening amounts.

A significant amount of the large classification of "Fruit" is anything but. Inbred, Crossbred Fructose bombs does not a Fruit our ancestors would have recognized make. Some of todays fruits are so laden with excess sugar, that arguing their health benefits is silly. I think that we have a secondary issue with these arguments, because, in my opinion, Dates, Raisins, Figs and other high Fructose load super sweet fruits are bastards. Berries or Avocado on the other hand are a great example of super low fructose(and low sugar) fruits that I believe the positives may outweigh the negatives. While I dont believe that strawberries are optimal for my health, I sure do enjoy them in "moderation". I have a healthy liver and no desire to lose more fat, and enjoy them enough to give up minutes at the end of my life if it comes down to it.

High Fruit intake affects teeth. Not going to argue about sugar and tooth decay. Brush your teeth after eating any sugars.

We already tell people their refined sugar is bad, if we tell them their "healthy" sugar is bad too, we will have a revolt. You'd never get a fruit based study funded. In addition, similar to if you want to test LONG term effect on moderate intake, youre hoping for empirical surveys at best.

So what we have right now, is scientific proof that fructose separated from fruit is undeniably bad. thats proven over and over again. Then we have Empirical evidence, that fruit seems to cause the same things that the separated fructose did.

Thats the best we can go on until we are given evidence to the contrary.

My personal recommendation is Minimal(not zero) rather than Moderate after your Liver and Weight are healthy.

Philosopher · Answer 3 · 2011-01-16 19:54:15Z UTC

There is some degree of semantic confusion about the word fructose. The negative studies that I have seen refer to HFCS "high fructose corn syrup" a synthetic derivative of corn that is NOT present in any fruit. http://www.diabetesincontrol.com/component/content/article/64-feature-writer-article/4486&Itemid=8 HFCS normally contains between 42% and 55% of fructose, plus glucose and polyssacharides and several studies show that a large intake of HFSC (not fructose per se!) is dangerous. Again this is about large consumptions of a derivative product that contains fructose together with GLUCOSE and other sugars. Fructose "per se" as contained in apples or bananas is a rather neutral sugar, and I am not aware of any study showing negative effects from the consumption of fructose per se and much less of any study showing negative effects of fruit consumption. So go ahead, have your apple, your banana and your orange, as long as you stay away from industrial HFCS!

Donis Fylaktou · Answer 4 · 2011-07-05 16:35:13Z UTC

I have had gout for years, and tried just about everything without success.I reduced meat to, minimum once a week, stopped alcohol altogether.I was having LOTS of fruit and vegetables and my gout was worsening. Finally I have read something about Excessive fructose increasing uric acid.I experimented reducing my fruit intake to 2 a day, and bingo within days I saw a dramatic improvement.Cherries are the only exception. I eat a lot of them when in season,with no ill effects.

Stancel · Answer 5 · 2011-01-16 20:24:17Z UTC

The liver can use fructose to replenish glycogen. So fructose is possibly only an issue in people with sedentary/over-eating habits, and that's when they're consuming loads of HFCS in soft drinks. Not relevant to people who eat healthy natural foods containing fructose like fruit and vegetables.

http://healthcorrelator.blogspot.com/2010/06/fructose-in-fruits-is-good-for-you.html

James · Answer 6 · 2011-01-16 19:23:17Z UTC

I've not seen any research on "moderate" intake. As far as I know, it's not really an issue for healthy people (we're not keeling over from eating an apple for example). The stuff I see pretty much says it's good to have "moderate" intake, not for the fructose, but because of the other nutrients in the food...

The real issue is that fructose is in a ton of things in the Standard American Diet in the form of High Fructose Corn Syrup. It's "only" 55% Fructose (compared to 50% in regular table sugar) and that 5% adds up fast. Plus, it's ONLY metabolised in the liver (glucose is throughout the body).

I'd recommend watching Dr Lustig's presentation "Sugar the Bitter Truth":

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

Paola · Answer 7 · 2011-01-17 00:47:42Z UTC

Fructose malabsorption seems to be a fairly common problem, which mostly causes digestive distress like bloating and mood disturbances. Most people using this site probably don't consume HFCS, but what about fruit? Fruit may cause problems too. The severity of a person's response depends on (at least) three variables:

Individual sensitivity
Total amount of fructose consumed
Ratio of fructose to glucose (the higher the glucose, the easier the absorption). So, a fruit with high fructose content can still be easier to process if the glucose content is high too (for example, bananas). Water melon, apples, pears, are among the worst offenders. See this: http://www.thepaleodiet.com/nutritional_tools/fruits_table.html

Sorry that I'm not providing more websites for this info, I read it a while ago, but lost all the sites when my computer passed away. Google "fructose malabsorption".

Bread-Eating Beelzebub · Answer 8 · 2011-07-05 16:59:41Z UTC

I take the TS Wiley approach, even though I'm not a fan of some of her other ideas. In Lights Out! she says that Vitamin D and increased activity during warmer months probably counteracts any negative effects of eating fruit. I lost all the weight I wanted to and fruit has certainly never made me gain weight.

The thing is, there isn't much evidence either way. We have some n=1 from some people who seem to have a tendency to gain weight because of previous metabolic damage. We have some reductionist folks like Lustig, but even he says fruit is OK! We have some population-level ideas from societies like the Kitavans, who eat fruit and are quite healthy. The idea that fruit is bad is a fringe idea.

Mark V · Answer 9 · 2011-05-15 20:05:32Z UTC

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Knowing what Paleos understand about insulin I think we can all agree that sugar and fructose should be a very "careful" and minor addition to the diet.

answered May 15 2011 at 20:05

Mark V
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	Not sure what you mean, fructose doesn't stimulate insulin. IMO the insulin=fat theory is bunk and there are a lot more factors to fat gain. – cliff Jul 3 2011 at 4:40
	lol. I eat more fruit in a day than most paleo people eat in a month. I leaned out somehow despite this.. And my skin is clearing up without regressing for once. Fructose must be... the devil? – Zach Aug 21 at 10:40

Michal · Answer 10 · 2012-08-21 09:15:25Z UTC

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About 40% of people have fructose intolerance. This suggests that majority of the people are not adequately adapted to higher intake of fructose. The best natural (paleo) source of fructose is honoey. Negative metabolic effects of fructose in honey and some fruits can be compensated by various healthy components in these food sources.

answered Aug 21 at 9:15

Michal
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Yup, fructose is a signal that tells us, it's late summer, we're eating lots of ripe fruit, it's time to store calories for winter when there'll be little food around. Likely since we only are capable of processing small amounts of fructose vs glucose, it means the fruits we evolved to eat did not contain huge amounts of fructose vs glucose and vs fiber, so no matter how much we binged our livers could handle it. Modern SAD sources of fructose overwhelm our liver's ability to process it and leads to fatty liver disease, similar to what alcohol does in huge amounts. – raydawg Aug 21 at 10:06

Zach · Answer 11 · 2012-08-21 10:35:47Z UTC

You people are ridiculous..

I've been doing my high-fruit, high-tuber, meat, eggs, coconut, some veggies, etc paleo diet model for months now. I eat LOTS of fruit every day, and continue to feel amazing in every way.

Almost like a Kitavian, perhaps?

Talldog · Answer 12 · 2012-09-10 17:32:18Z UTC

Define moderate.

Most people define moderate in relation to the current trends. Because HFCS (high fructose corn syrup) has become ubiquitous, 20% of the typical American's daily calories come from HFCS And, since HFS is 50% furctose, that means 10% of their daily calories are fructose from HFCS.

Plus, you need to add in the fructose calories consumed from other sources like fruit and honey. For this example, let's say that's 5%.

So, 15% of the typical American's calories come from fructose.

200 years ago I'd wager no more than 5% of calories came from fructose (as fruit was seasonal and sugar of any type was in short supply--and both were expensive).

So what's moderate? 12%, 10%, 8%, 5%? By today's standard maybe, but not by 1800 standards.

Nancy · Answer 13 · 2012-09-10 17:10:01Z UTC

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Really enjoying this thread. Something Chris Masterjohn said re AGEs is niggling in the back of my mind... off to see if I can find it...

answered Sep 10 at 17:10

Nancy
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What evidence that moderate fructose intake is bad for the healthy?

13 Answers