Hack This: Moderate Fructose Impairs Insulin Sensitivity

mmartian

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Stephan Guyenet just tweeted this study:

Moderate Amounts of Fructose Consumption Impair Insulin Sensitivity in Healthy Young Men
A randomized controlled trial

Abstract

OBJECTIVE Adverse effects of hypercaloric, high-fructose diets on insulin sensitivity and lipids in human subjects have been shown repeatedly. The implications of fructose in amounts close to usual daily consumption, however, have not been well studied. This study assessed the effect of moderate amounts of fructose and sucrose compared with glucose on glucose and lipid metabolism.

RESEARCH DESIGN AND METHODS Nine healthy, normal-weight male volunteers (age 21–25 years) were studied in this double-blind, randomized, cross-over trial. All subjects consumed four different sweetened beverages (600 mL/day) for 3 weeks each: medium fructose (MF) at 40 g/day, and high fructose (HF), high glucose (HG), and high sucrose (HS) each at 80 g/day. Euglycemic-hyperinsulinemic clamps with [6,6]-2H2 glucose labeling were used to measure endogenous glucose production. Lipid profile, glucose, and insulin were measured in fasting samples.

RESULTS Hepatic suppression of glucose production during the clamp was significantly lower after HF (59.4 ± 11.0%) than HG (70.3 ± 10.5%, P < 0.05), whereas fasting glucose, insulin, and C-peptide did not differ between the interventions. Compared with HG, LDL cholesterol and total cholesterol were significantly higher after MF, HF, and HS, and free fatty acids were significantly increased after MF, but not after the two other interventions (P < 0.05). Subjects’ energy intake during the interventions did not differ significantly from baseline intake.

CONCLUSION This study clearly shows that moderate amounts of fructose and sucrose significantly alter hepatic insulin sensitivity and lipid metabolism compared with similar amounts of glucose.

http://care.diabetesjournals.org/conten ... 0.abstract

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What say we?
 

charlie

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Can someone please translate this to layperson terms? Thank you!
 

nwo2012

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Very small sample size already makes the results rather 'ordinary'. How do we know, in such a small sample, what else these subjects ate? Other possible sources of fructose, glucose etc. Which fats were they eating? It could be a high PUFA diet for all we know. So even without going into the results, there are already many variables that could affect the outcome. Who funded the study and what were the authors' biases? So many questions.
 

cliff

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No way to interpret the study by just reading the abstract.
 

nwo2012

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cliff said:
No way to interpret the study by just reading the abstract.

Also very true.

This quote of Danny Roddy's site also adds to the points I made. Even if the full study were read and suggested 'harm' from higher fructose, on a background of what other consumption?
These guys could be on 'the pill' for all we know. :neener

My interpretation of Peat's philosophy is that excess sugar will be used "constructively" in an organism with an efficient oxidative metabolism. It is only in the face of excess PUFA, estrogen, serotonin, cortisol, and adrenaline that sugar is misused by the body
 

nwo2012

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Damned nightshift, doing my work but things keep popping into my head.

Nine healthy, normal-weight male volunteers

Healthy by what definition? Could have a LOT of PUFAs stored in their tissues being release as they improve thier thyroid function with the extra fructose? Could have hypothyroidism. So many variable and only studied for 3 weeks at a time. Useless study.
 

cliff

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The problem is that they think certain health markers are bad like increased cholesterol production which is actually good. Or raised triglycerides which could be protective against free fatty acids. Getting excess refined sugar without the proper nutrients could cause issues as well.
 

nwo2012

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cliff said:
The problem is that they think certain health markers are bad like increased cholesterol production which is actually good. Or raised triglycerides which could be protective against free fatty acids. Getting excess refined sugar without the proper nutrients could cause issues as well.

Yes raised cholesterol can be good in some circumstances. It can also be indicative of hypothyroidism in some circumsances due to poor conversion into steroid hormones.
 

cliff

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nwo2012 said:
Yes raised cholesterol can be good in some circumstances. It can also be indicative of hypothyroidism in some circumsances due to poor conversion into steroid hormones.


High cholesterol is indicative of hypothyroidism. Substances that raise cholesterol(like sugar) are good either way. The problem isn't high cholesterol; the problem is low thyroid.
 

nwo2012

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cliff said:
nwo2012 said:
Yes raised cholesterol can be good in some circumstances. It can also be indicative of hypothyroidism in some circumsances due to poor conversion into steroid hormones.


High cholesterol is indicative of hypothyroidism. Substances that raise cholesterol(like sugar) are good either way. The problem isn't high cholesterol; the problem is low thyroid.

Yes I agree. What I meant is it can be a good indicator, I didnt mean it is actively contributing to the problem. (i.e. I know its an innocent bystander). Just so you know I know. ;)
It's like the whole high cholesterol leads to heart disease hoopla, so they give out statins. Nevermind that sure the hypothyroidism that is present will increase the odds of heart disease, not the innocent cholesterol which is given all the blame.
 

nwo2012

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RP

Usually, the anti-fructose diets include enough PUFA to account for the effects. In this case, deconstructing, not just debunking, is needed. Their conceptual framework represents a current medical obsession, and it's based largely on a vacuous idea of "insulin sensitivity." Insulin does many things; fructose does some of the good things insulin does, such as promoting glycogen stores, and increasing cellular respiration. 
 

Andrew Kim

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The only reliable effect of eating fructose is elevated triglycerides, the significance of which is still open to question.

Other clamp studies in humans have shown the opposite result and as a whole, the studies on fructose are actually favorable, in humans, that is.

Studies of this ilk are, really, useless because they only last 2 or 3 weeks and pure fructose is given; no one eats pure fructose, especially in the amounts used, and I've read at least 2 long term studies, one in monkeys, that demonstrated no metabolic differences after a few months on either glucose or fructose.
 

Kemby

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Andrew Kim said:
The only reliable effect of eating fructose is elevated triglycerides, the significance of which is still open to question

I'm still trying to make sense of the differences of opinion between those "Paleo" and those "Peat" in regards to this.

Chris Kresser and other have said that a high triglycerides to Hdl ratio indicates a high risk of heart disease.

I would be interested to hear opinions on this and why it is still "open to question" as andrew stated.

Martin
 

montmorency

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Guyenet is a Paleo guy isn't he.

In recent years, war has been declared on Fructose by such as he. Robert Lustig is another.

I used to go along with it until I read Ray Peat.

I don't know who is "right", but I think it is important to keep an open mind and ask crtiical questions, using the scientific method.

Richard Feinman (not the physicist, "the other one) calls people like Lustig "Fructophobes", which is interesting, because Feinman is himself a low-carb guy.

rdfeinman dot wordpress dot com


I'd love to see a debate between Ray Peat and Richard Feinman.

On sugar and diabetes, for example.
 

stargazer1111

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I know this is a really old post. But, I wanted to let others who come across this know something. I am a biochem student at the University of Michigan and have free access to all published papers on pubmed. I read the full paper in the original post. It does not detail what the subjects ate at all. It only mentions these sugary drinks that were made by Nestle corporation, each containing different amounts of fructose, glucose and/or sucrose. They were required to drink the drinks with their main meals. Yes, the meals were weighed and recorded. The problem is, they didn't put any of that in the paper. It looks like it was in a hospital setting. So, they were probably eating the usual hospital food which means lots of PUFA.

This study is abominable.
 

stargazer1111

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Here is exactly what they wrote about their diets: "Dietary intake was assessed at baseline and after each of the four interventions. The consumption of energy, macronutrients, fiber, and the different sugars are reported in Table 3. Energy intake and the percentage of energy from fat, carbohydrates, and protein did not differ significantly between HG and the other interventions, and neither did fiber intake. However, protein intake was significantly lower in all interventions, except for HS, compared with baseline, whereas fat intake was significantly lower in the MF and the HS interventions, again compared with baseline. Carbohydrate intake was higher in the HF, HG, and HS interventions compared with baseline, but the differences were not significant. The consumption of the individual sugars varied according to the interventions."

They did not specify the types of fatty acids consumed. If they were eating a lot of PUFA, this might explain the results.
 

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