Thursday, October 27, 2011

Insulin Myths Dispelled

Jame Krieger dispels myths about insulin in his series on the hormone starting with Insulin....An undeserved bad reputation

10 comments:

Thomas said...

Don-this is an excellent series. It helps to set your head straight after being exposed to loads of traditional low-carb dogma.

Peter said...

Jame Krieger writes,

"In fact, if you truly wanted to keep insulin as low as possible, then you wouldn’t eat a high protein diet…you would eat a low protein, low carbohydrate, high fat diet. However, I don’t see anybody recommending that".

this is were the author completely drops the ball. That's what I reckon.

"A study done at Tufts, for example, presented at the 2003 American Heart Association convention, compared four popular diets for a year. They compared Weight Watchers, The Zone Diet, the Atkins Diet (almost no carbs), and the Ornish Diet (almost all carbs) for a year. The insulin levels of those instructed
to go on the Ornish diet dropped 27%. Out of the four diets that were compared that year, Ornish’s
vegetarian diet was the only one to significantly lower the 'Monster' 'Hormone That Makes You Fat,' even though that’s supposedly what Atkins and The Zone diets were designed to do.

Michael Greger, "Atkins Exposed".

"One Year Effectiveness of the Atkins, Ornish, Weight Watchers, and Zone Diets in Decreasing
Body Weight and Heart Disease Risk"

by Michael L. Dansinger, Joi L. Gleason, John L. Griffith, Wenjun
Li, Harry P. Selker, Ernst Schaefer; Tufts University, New England Medical Center, Boston, Mass.

Don said...

Peter,

I also think James made a mistake there. We have too much evidence that high saturated fat intake induces insulin resistance, which tends to raise insulin levels...and this may explain why people attempting the Ornish approach (less than 10% total fat) had the largest decline in insulin levels when compared to those other approaches.

Will said...

Don,

"We have too much evidence that high saturated fat intake induces insulin resistance, which tends to raise insulin levels..."

This is not my understanding. Fat-induced insulin resistance is physiological, and actually differs from pathological insulin resistance. Peter discusses it here:
http://high-fat-nutrition.blogspot.com/search/label/Physiological%20insulin%20resistance%20%281%29

In short, your body adapts to a VLC diet by *reducing* insulin levels, so as to make serum glucose more available for uptake by the brain. While different from chronic hyperinsulinemia, it seems the jury is still out as to whether or not it's safe to remain in this state long-term.

Whether fat contributes directly to any kind of insulin resistance is unclear to me. It seems very low carb / ketosis is the necessary condition for it.

Or are you aware of a different mechanism? If so, I'd be interested in any reference you can provide me. Thanks!

Will said...

"Protein spikes insulin too" sounds good at first, but does not wind up being all that convincing, unfortunately. Dietary protein appears to stimulate glucagon release, which counteracts many of the effects of insulin. Glucagon opposes fat storage, encourages fat release, and opposes insulin-induced reactive hypoglycemia by stimulating glucose release from the liver. (Perhaps glucagon also increases insulin sensitivity? I haven't seen any mention of such though)

Don said...

Will,

Do you still believe that insulin makes people overeat and get fat, and that we have to counteract insulin to prevent fat gain?

If so, you need to read Krieger's full series.

Insulin is NOT the reason people gain fat. You can get and remain fat with low insulin levels, or even if the protein you're eating stimulates glucagon release.


By the way, why does protein ingestion stimulate glucagon release? Only if the protein is excess, in which case the reason glucagon rises is to stimulate conversion of the excess amino acids to glucose! Which then causes a rise in insulin.

In other words, this is the mechanism by which the body converts excess amino acids to glucose, and when this glucose derived from amino acids enters the blood, it will suppress fat burning.

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/glucagon.html

The whole idea that eating excess protein stimulates fat burning by raising glucagon levels is simply false, apparently based on ignorance of the reason a high protein intake stimulates glucagon output.

Don said...

Will,

http://www.ncbi.nlm.nih.gov/pubmed/12079860

http://www.ncbi.nlm.nih.gov/pubmed/9329762

http://www.ncbi.nlm.nih.gov/pubmed/15297079

http://www.ncbi.nlm.nih.gov/pubmed/11317662

Takeaway: Increasing the proportion of fat in the diet reduces insulin sensitivity in humans, and the effect is greater (more insulin resistance) the greater the proportion of saturated fats in the diet, but somewhat less if the fats are unsaturated. The best way to increase insulin sensitivity is to reduce total dietary fat, irrespective of type.

Will said...

Hi Don,

I first read Krieger's series (in full) some eight months ago. That's also the time I stopped believing the carb/insulin hypothesis. As of today my own diet is probably > 60% carbs, and I'm eating roasted pumpkin as I type this. So let it be known that I love my carbs :)

That being said, there are some loose ends which I could not resolve. Glucagon was one of them. (Carbs and small-dense LDL is another, if you care to comment on that.)

I hadn't looked into why protein stimulates insulin (or glucagon) in the first place, so thanks for pointing it out. If I understand you correctly, then protein, if not consumed in excess, would trigger neither insulin or glucagon?

It seems like most everybody leans on that one KANWU study connecting saturated fat with insulin resistance. At least 2 of the 3 review papers you cite above rely on it. The actual study showed a small difference between SAFA and MUFA, with only borderline statistical significance at the 5% p-value mark. It would be nice to see additional studies to confirm this data, but if the effect is small it probably doesn't matter anyway in the context of a low-fat diet, as you said. Which is generally how I eat anyway, being of Asian-descent.

Will said...

Oh yes, I forgot to mention one thing. If high-fat feeding can induce physiological insulin resistance, then the argument goes that it may not be of concern as long as you stick to a low-carb diet. According to Peter @ Hyperlipid, this type of insulin resistance is 100% normal and completely reversible.

Not that I would risk it, myself.

Mzlittlekitten said...

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