Banting or ranting?

This story was produced by Health-E News.

Banting is the flavor du jour in middle-class South Africa, and many people have swallowed Professor Tim Noakes’s low-carb, high-fat philosophy without question. Not that you can blame them – who wouldn’t want to lose weight by eating bacon?

Despite warnings from doctors and dietitians about the potential danger of a diet rich in animal fats but low in vegetables and fruit, the Banting movement is gaining traction, mainly because people do lose weight initially. Sales of Noakes’s Real Meal Revolution cookbook have rocketed to over 200,000, massive by South African standards, and restaurants and bakeries are offering 'low-carb' or 'banting' options.

Last week, Noakes and Jonno Proudfoot brought out a second cookbook, Raising Superheroes, to help pro-Banting parents raise their children in a pro-Banting way. Ironically, the Health Professions Council of South Africa is in the process of conducting a hearing into Noakes after a complaint of misconduct was laid against him for advising a mother on Twitter to wean her baby onto a low-carb, high-fat diet.

Noakes says his diet is aimed at people suffering from insulin resistance (which he says is most of us), and he advocates eating around 50g of carbohydrates a day (about the equivalent of what you would get from an apple), which means most starchy vegetables and almost all fruit have to be excluded. Dieters are meant to substitute the lack of carbs with fats, particularly saturated animal fat like butter and fats derived from meat, but also including fats from nuts, olive oil, avocado, etc.

While Noakes has plenty of fans, he has also come under fire for making claims about the low-carb, high-fat diet that are not supported by scientific evidence and are, in some cases, actually the opposite of current medical advice.

I looked at three of Noakes’s controversial statements and weighed up the evidence. The first has become one of the pillars of Noakes’s dietary theory: “The majority of us are insulin resistant”.

In his book, The Real Meal Revolution (pages 23 and 258), Noakes states that the “majority” of people are insulin resistant, and in an e-ail to me he confirms his stance, saying “many people are insulin resistant”. He also says in a BizNews article: “in my view, most people are [insulin resistant] these days”.

Insulin is a hormone secreted by the pancreas to help the body absorb glucose and use it for energy. With insulin resistance, the pancreas still produces insulin, but the body does not respond to it as it should and unabsorbed glucose ends up in the bloodstream. Insulin resistance is a known precursor of diabetes, but Noakes also links it to hyper-cholesterolaemia (very high cholesterol levels – LDL of 7.5mmol/L and greater), high blood pressure and obesity.

As carbohydrates are converted to glucose in the body, Noakes argues that, by removing the source of glucose (carbohydrates), there is no need for the body to absorb and process glucose, and that a person will therefore be spared the resulting medical issues. Noakes has gone so far as to say that, “for people like me, who are insulin resistant, if you eat carbohydrates, you will die. The only solution is a high-fat diet”. But endocrinologist Professor Tessa van der Merwe says there is no scientific proof in any local or international literature to support the theory that most people are insulin resistant. It is costly and complicated to test for insulin resistance, and in general medical practice someone is considered to be insulin resistant when blood tests indicate pre-diabetes.

Although an increased insulin level is one of the symptoms of insulin resistance, it does not mean that a state of clinical insulin resistance has been reached, Van der Merwe explains. Although the exact percentage of insulin resistance in the population is unknown, only diabetic patients and people with proven laboratory glucose intolerance have reached a state of clinical insulin resistance.

Van der Merwe, an honorary professor at the University of Pretoria and the CEO of the Centre of Excellence for Metabolic Medicine and Surgery of South Africa, says insulin resistance is a complex medical condition that is a consequence of weight gain, rather than a cause of it, as Noakes suggests.

“In fact, one of the functions of insulin in the body is to act in an anti-lipolytic manner (meaning it prevents fat from storing in the adipose tissue). If so many people were insulin resistant, theoretically we would have a nation that no longer gains weight,” says Van der Merwe.

Noakes claims that “the only solution”, if person is insulin resistant, is a high-fat diet. But Van der Merwe warns that a diet high in saturated fat may actually aggravate insulin resistance: “In the very early stages of insulin resistance, free fatty acids release rapidly from the fat tissue … if an excess amount of saturated fat is added, cell death [in the pancreas] will take place through the production of certain toxic chemicals. It is like pouring fuel onto the fire.”

The second of Noakes’s most common and controversial claims is that “the low -carb, high-fat diet reverses all known risk factors for heart disease”.

There are different types of heart disease (eg inherited heart problems or others caused by infections). One of the most common causes is coronary artery disease, which occurs when the major arteries leading to the heart becomes damaged or diseased due to plaque build-up which hampers the flow and blood.

The current accepted medical understanding is that high levels of LDL, the so-called 'bad' cholesterol, is one of the main causes of plaque build-up, which results in coronary artery disease, heart attack and even death. One of the common causes of elevated LDL cholesterol is saturated (animal) fat – a key ingredient in Noakes’ low-carb, high-fat diet.

Noakes has