Saturday, August 24, 2013

The Nutrition Debate #137: “How Ketogenic (Low Carb – High Fat) Diets Work”


Once again, the Low Carb Diet News site keyed me in to another blogger who was new to me and who thinks along the same lines as I do. He is a New Zealander named Professor Grant Schofield, and he blogs on “The Science of Human Potential” here. He is also an academic (Psychology) at the Auckland University of Technology, NZ, which leads to an interesting digression in his post that I liked well enough to repeat here. To quote “Professor Grant” (as he is known):

“A second excellent review article was also published in Nutrition Today by Volek (again!) and Phinney, the low carb gurus. This one is called “A New Look at Carbohydrate-Restricted Diets: Separating Fact From Fiction”. Again this is an excellent scientific review paper. What I should be doing in this blog is simply drawing your attention to this good work and you can go and check it out for yourself. Except I’m aware that unless you work at a university, that’s easier said than done. You’d have to buy the papers, which means that most of the people who stand to benefit from the knowledge won’t.”

How true. The new Volek and Phinney paper that the good professor was referring to is published in “Nutrition Today,” for the journal’s pecuniary benefit alone, and is available for $48 plus tax for this one article or $99 for an annual subscription. I passed on this offer, and am grateful that the professor reviewed the piece for me (us). But just think of all the practitioners out there, the very clinicians who would benefit from this the most, who will never see it for lack of an academic appointment, and the time to read it. What impediments we make to the advancement of learning!

Anyway, Professor Grant goes on to list his takeaway of the main points of the Volek and Phinney scientific article. He does gets a bit “in the weeds” so, as J. Stanton says on his Gnolls.net website, “CAUTION: CONTAINS SCIENCE.”  The “Professor Grant” article, including the four points below, is found here:

1.      Saturated fat levels in the blood are not associated with dietary saturated fat intake, but dietary carbohydrate intake. They show evidence from both randomized controlled trials and population data for this.

2.      They discuss in detail what the keto-adapted (fat adapted) state is; how this comes about, including increased beta oxidation of fat, decreased hyperinsulinemia, and a re-orchestration of substrate utilization in the body, including the use of ketones to fuel brain function. It is interesting that the majority of practicing dietitians, endocrinologists, cardiologists, and public health physicians have never heard of any of this.

3.      They point out what is a very important and obvious set of outcomes, which are well documented in the scientific literature; that treating a patient with insulin resistance with a low fat/high carb diet is palliative and going to make the problem worse. If you are having trouble getting glucose into your cells, then reduce the glucose load stupid!

4.      They show a nice little diagram, which I have reinterpreted and redrawn below, to show the role of dietary carbohydrate in metabolic (dys)function. To quote the authors “The major point is that SFA (saturated fatty acids), and the response to eggs, has a totally different metabolic behavior when consumed in the context of a low carbohydrate diet.”

Here’s a link to Professor Grant’s re-interpreted JPG diagram. The interesting aspect of Volek and Phinney’s thesis to me is that first sentence in bullet Number 1 above, as illustrated in Professor Grant’s diagram. Take a look, or a second look, at it. They are showing with “both randomized controlled trials and population data for this,” that “high dietary carbohydrates” (symbol: CHO) results in “SFA synthesis up” and “SFA storage up” (we make and store more body fat in the form of triglycerides). That in turn, in the “metabolic health continuum,” leads to “plasma SFA up” (high blood fat, i.e. triglycerides), “insulin resistance up,” and “dyslipidemia up.”

The other side of the diagram shows that the inverse is true with lower dietary carbohydrate intake. Okay, this is a little heavy on the science. My wife likes to simplify it all by telling our friends and acquaintances that “Eating fat doesn’t make you fat; carbohydrates make you fat.” I like that. Most people just look at her in wonderment and disbelief. Some say, politely, “I never heard that before.” I secretly wonder if they think she is crazy. She’s not a scientist or a doctor, and doesn’t even play one on TV. Where does she get these crazy ideas? Maybe she reads my blog. Maybe she doesn’t believe everything she hears on TV, or reads in the popular press. Maybe…just maybe…the word is gradually seeping out there that “the conventional wisdom,” that we have been following for the last 50 years, has been wrong. Maybe it HAS all been a big fat lie, as Gary Taubes suggested in his seminal NYT piece, which appeared on the cover of the Sunday magazine on July 7, 2002. If you’ve never read it, you can access it here.

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