Saturday, 28 January 2017

The Old Ivory Tower v Nutritional Knowledge

The "trial" of Dr Tim Noakes, is a front for an attack by the nutrition establishment on the Banting Diet. What is the nutrition establishment? In South Africa, it's represented by Stellenbosch University, the dietitians, nutrition scientists, most doctors, and the government departments that control these professions. But more than that, all of these professional bodies have close ties with industry the provide the money, that pays the salaries of key people.

The Banting Diet is a threat to the sugar industry, bakers, grain producers, bread, biscuit and confectionary manufacturers, it's also threatening to the government. The Banting diet demonstrates that the wages of ordinary people cannot sustain a healthy diet. That food based on corn, and corn and more corn, no matter how you dress it up, is poor quality food and an entirely inadequate diet. A diet lacking in animal fats is cheap, but it isn't a healthy diet. That message is dangerous. Powerful forces want to discredit it.

In South Africa, as the proceedings come to an end, in April, it's the established dietary practice that is really on trial, not Dr Noakes. Fortunately, at least in South Africa, and at least on the narrow point, of weaning small children, "official" recommendations have recently changed, and are in line with current science. On the specific issue of a diet for weaning, the official advice and Dr Noakes agree; Noakes is not guilty, and the official advice gets a pass mark.

However, that result will not serve the interests of the establishment, which needs a clear condemnation of very low carbohydrate diets, Banting Diets, for adults. The Stellenbosch University - Cochrane Collaboration Review: "Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A systematic Review and Meta-Analysis," provides justification of the current dietary standards in South Africa. The study concludes that a low-carbohydrate diet has no advantages over the standard low-fat diet for weight reduction or cardiovascular risk.

This paper is offered as "proof" that there is no value in the Banting Diet. Banting requires you to significantly reduce your consumption of the cheapest foods available. Banting asks people to live almost entirely on protein and fat. Stellenbosch argues two points further against Banting, they say, "It is plausible that these low CHO diets could be harmful, especially over the longer term." They also state that the diet can't be maintained, and that people will revert back to their old dietary pattern, and put their weight on again.

This "conclusion" isn't in line with my own experience. I read the study, with disbelief. But the problem is in the language, and the definition. Low-carbohydrate for Stellenbosch, is defined as less that 45% of the diet from carbohydrates. The average dietary intake for 14 "low-carbohydrate" studies was 35% carbohydrate, 35% fat and 30% protein. That's very different from the 5% to 10% carbohydrate and 80% to 85% fat, of a genuinely low-carb, high-fat diet.

Converting to grams of carbohydrate: Low-carbohydrate for Stellenbosch, is defined as less that 240gm/d. Studies included had carbohydrate intakes less than 191gm/d. For the 14 studies I could get numbers for, the average is 180gm/d. NONE of the studies used had fat intake above 50% of total energy.

Compare that with what Banting recommends. Benefits begin when carbohydrates are less than 120gm/d, but ketosis is not achieved reliably until intake is as low as 50gm/d and even better at 25gm/d. This means that your fat intake needs to be 70% to 85% of your diet. So while the Stellenbosch University - Cochrane Collaboration Review: is consistent within itself, it does not look at very-low carbohydrate diets at all. The Stellenbosch University - Cochrane Collaboration cannot say that the Banting Diet is the same, or more, or less effective, for weight loss and cardiovascular risk, because they made a deliberate choice not to test that.

The conclusions the Stellenbosch University - Cochrane Collaboration Review makes are actually consistent with very-low-carbohydrate studies done by other people. Studies that were excluded from the Stellenbosch University - Cochrane Collaboration Review (I expect excluded for a reason, they undermine the desired outcome.). For instance this study is revealing; Effects of Step-Wise Increases in Dietary Carbohydrate on Circulating Saturated Fatty Acids and Palmitoleic Acid in Adults with Metabolic Syndrome," by B.M. Volk et al. Very briefly; above 400gm of carbohydrates a day weight gain can be expected, in a broad range down from 346gm/d to 179gm/d weight seems to be stable. At 131gm/d weight loss picked up, at 83gm/d and 47gm/d the rate of weight loss significantly improved.

Stellenbosch University tells us that there is no advantage in a low-carbohydrate diet. BUT the low carbohydrate diet they are referring to, has an average carbohydrate intake of 180gm/d. The study by B.M. Volk et al agrees with that. They show that weight loss began to be significant at 131gm/d, and was much stronger at even lower carbohydrate levels.

We can see here that carbohydrate restriction certainly works, but the best results require a very strong restriction that put the body into ketosis. That's not hard to do, but it is unusual, and it does require good understanding of the science and the dietary method for people to do this successfully. You can't instantly become an expert, it takes time and considerable study to gain the knowledge required.

There are many misstatements of fact in the Stellenbosch University - Cochrane Collaboration Review, statements of prejudice, I believe, rather than a deliberate misrepresentation of that science. For instance "When foods high on CHO are avoided, and replaced with high protein foods, reliance on animal protein sources becomes necessary." Who can argue with that? It's sentence that makes the same point twice. Once as a proposition and once as the obvious result. The problem is that this statement misrepresents what the Banting Diet says. In Banting, carbohydrate is replaced with fat, particularly with saturated fats, which for too long have been lacking in our diet.

Stellenbosch University and friends, are so lipophobic that the can't imagine a diet 70% or 80% fat. That prejudice appears over and over in their review.

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