Practical Paleo: High Fat Diets

This blog was inspired by one of my favourite sources of paleo information, the legendary Robb Wolf and his podcasts and the unfortunate fact my dad is a slowly developing fatty who is trying to accumulate metabolic syndrome like it’s going out of fashion.

After ranting on to him about his prescription of statins for high cholesterol and trying to explain to him (a pasta loving Italian) that a high-fat low-carb paleo diet will improve/eradicate his bad cholesterol, his ‘doctor’ (I hesitate calling him this) said a paleo approach would aggravate his condition/insulin resistance and a high-carb diet (fucking idiot) would be better for him.

This pissed me off as this advice has crushed any buy-in I got from my dad because his ‘doctor said so’ and more importantly HIGH-CARB DIETS CAUSED METABOLIC SYNDROME. Palaeolithic man wasn’t feeding on nutrition-less fructose (a poison) and massive amounts of sugar/ refined grain or food with no nutritional content.

Back to the Robb Wolf loving……..

Recently Matt Lalonde a PhD biochemist from Harvard University (unleash the kraken!) was hosted on the show, I Loved this episode and have listened to it about 10 times!

This post will attempt to address some of the topics mentioned on the show that I found particularly interesting; the difference between physiological and pathological insulin resistance.

Matt begins off the bat stating that a high fat low carbohydrate (CHO) diet (paleo) will increase insulin resistance – however this is not pathological.

This is confirmed by Johnson et al. (2006). Johnson et al. Investigated insulin resistance by feeding 7 healthy, fit males one of three (lasting 67 hours) dietary interventions: (1) a water only starvation diet (S) (2) a low CHO high fat diet (LC – paleo) and (3) a mixed CHO control diet(C).

Prior to participation each individual was fed a standardised meal of CHO (50%) protein (35%) and fat (15%) followed by 60 minutes of moderate intensity cycle exercise. These measures were “designed to standardize endogenous substrate availability prior to the dietary manipulation in addition to controlling for effects of exercise on subsequent insulin sensitivity and glucose tolerance”. After exercise the participants were fed a meal respective of their dietary intervention S, LC or C.

After completion of the experimental trial, intra muscular triglycerides (IMTG) were examined using proton magnetic resonance spectroscopy (I’m not even going to touch this) and insulin resistance was measured using an intravenous glucose tolerance test.

(The results are not reported in full, check out the full text)

Results show even though CHO intake was lower (p=.01) and fat intake was higher (p=.01) for LC than S, IMTG stores were not significantly different (p=.046) between groups. Similarly, plasma glucose post intervention did not significantly differ between LC and S (p=.013). Interestingly, glucose tolerance was impaired for LC (p=.05) and S (p=.01) however there were no differences (p=.029) between LC and S, moreover insulin sensitivity was higher for LC and S (p=.01).

Ultimately, the authors go on to discuss this as a natural physiological response to high fat low carb diets or CHO restriction as this (CHO restriction) was the only common factor between diets. They suggest IMTG accumulation is due to greater FFA’s in circulation, thus increasing insulin resistance.

Dr Lalonde suggests this is due to the fact that the brain needs CHO to survive, but may run on a mix of 25% glucose 75% ketone bodies. So the increased insulin resistance is just the body’s way of ‘protecting’ available glucose for the brain. This then causes the muscles to accumulate lipid stores, as they would with glycogen when there is a CHO rich environment.

Therefore, insulin resistance in this context from a high-fat low-carb paleoish style diet -does cause insulin resistance, just not in a pathological way that is caused by high-carb low-fat Neolithic diets.

I will do another post on pathogenic insulin resistance once I have read some studies and try to link it into this post!

Go and have a fatty (grass fed) steak, its good for you.

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2 Responses to Practical Paleo: High Fat Diets

  1. Great stuff!!

    Shame they don’t detail the actual fatty acid composition in the high fat/low carb diet.

    Lots of rodent studies that are cited as high fat/low carb diets cause pathological insulin resistance tend to be crap-ina-bag diets using corn/vegetable/soy oils for fats and are usually high in trans fats.

    Hmmm, so eating fats that don’t really constitute as food causes insulin resistance, go figure. If we had more info about this from the Johnston et al. study that may be another plausible explanation for the results.

    Peter at Hyperlipid has talked about this a lot. Here’s one post.

    http://high-fat-nutrition.blogspot.com/2011/02/144-solution.html

    He’s hilarious also!!

    • There is an abstract suggesting omega 3’s can prevent insulin resistance caused from high fat diets: http://www.sciencemag.org/content/237/4817/885.abstract

      So maybe a balanced omega 6:3 ratio would negate/reduce insulin resistance? However, as Dr Lalonde suggests this is a normal physiological response, so maybe insulin resistance is ok in the paleo context? Also, he mentions insulin resistance can save your life as when critically wounded, the body increases insulin resistance so when gluconeogenesis occurs (through secreted cortisol and adrenaline) all glucose is spared for the brain so maybe this is a good adaption?

      What would be interesting is if someone monitored insulin resistance before and after proper resistance training (in conjunction with a high fat diet), as this has shown to increase insulin sensitivity, what do you think?

      I have just received Light’s Out so maybe I will be enlightened after this, I need to re-read the paleo solution again, I think there was something like this in there, Oh well……..

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