Banting or ranting?
Truth or hoax – Tim Noakes has convinced thousands of people to follow his low-carb, high-fat diet, but do the central pillars of his diet stand up to scientific scrutiny?
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.
Diet may be like ‘pouring fuel onto the fire’ for those with insulin resistance
[quote float= right]Noakes likes to portray himself as a revolutionary who is fighting against the dogma of Big Pharma and the big food industry…Yet his banting diet has also become a form of dogma…
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.”
Not all heart disease is created equal
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 admitted that his diet will raise cholesterol levels (including LDL cholesterol) in some people. However, he does not consider it a problem as he ascribes to a theory that cholesterol is not linked to heart disease. In a letter to the Cape Times he explains that, according to reports in the American Journal for Clinical Nutrition and a Cochrane Collaboration, “there was no clear evidence for dietary fat changes on total mortality or cardiovascular mortality”. But he failed to mention that the same Cochrane report states that reducing saturated fat intake in the diet “reduces the risk of cardiovascular events (heart attack) by 14%”.
His theory is contrary to the view held by a wide range of medical experts including the World Health Organisation, the American Heart Association and the Heart and Stroke Foundation, all of which link high levels of LDL cholesterol to coronary heart disease.
Noakes’s claims about the reversal of risk factors for heart attacks have resulted in some patients exchanging their cholesterol-lowering statin medication for his low-carb, high-fat diet, according to cardiologist Dr Anthony Dalby at a recent public lecture. According to Dalby, this has resulted in patients presenting with cholesterol levels as high as 12 (the normal range is three to 5).
Other risk factors for coronary artery disease include high blood pressure (hypertension) and diabetes/insulin resistance. Both of these conditions can improve through weight loss – regardless of what diet is used to achieve weight loss.
Diabetes is a degenerative condition caused by the death of the beta cells in the pancreas, and once the cells have failed they cannot be restored. The extent of the cell damage determines the severity of a person’s diabetes. Mild cases can be managed through diet (which is what is meant by ‘reversed’), and moderate to severe cases have to be managed with diet as well as medication. In this BizNews interview, Noakes, who has type-2 diabetes himself, admits to taking diabetes medication in order to control his blood-sugar levels.
Cutting carbs won’t cut out cancer risk
[quote float= right]Most cancers have nothing to do with nutrition. Only about 15 percent of cancers are due to obesity and may be linked to nutrition and genetics”
Noakes’s third controversial claim is: “If you are not eating carbohydrates you don’t have to worry about cancer”. He made this statement on the KykNET actuality programme, Robinson Regstreeks (22:40). The Times article shows how he first denied saying it at all, but when presented with the evidence from the show, he said that he was only repeating what Dr Craig Thompson of the Memorial Sloan Kettering Cancer Centre said in a 2011 talk. In this BizNews article, Noakes explains that “cancer cells are proven to be utterly glucose dependent” and “cancer is a nutritional, carbohydrate-dependent disease, and that scientists need to work out ways to starve cancer cells of glucose”.
When I asked him about this claim, Noakes replied: “I did not say you will never NOT get cancer… I said that carbohydrates (and sugar) drive cancer … so if you are not eating a high-carbohydrate diet you will minimise your risk for cancer.”
This theory is based on work by Otto Warbug (a Nobel Prize winner in 1931), who hypothesized that cancer cells can only burn glucose. Noakes deduces that since carbohydrates turn to glucose in the body, one would starve cancer cells by not providing them with glucose.
But Dr Carl Albrecht, head of research at the Cancer Association of South Africa, says, “this is dangerous, wishful thinking” as it may prevent people from following tried and trusted prevention methods in a belief that they are immune to the disease. Albrecht explains that, although cancer cells do use glucose, they are not solely dependent on it and also use glutamine and amino acids as sources of energy.
Albrecht also disagrees with Noakes’s statement that cancer is a nutritionally driven disease. “Most cancers have nothing to do with nutrition,” says Albrecht. ‘Only about 15 percent of cancers are due to obesity and may be linked to nutrition and genetics.”
Albrecht adds that most cancers are caused by smoking, viruses, chemicals, environmental factors such as sun exposure and a genetic predisposition to the disease. This is supported by the National Cancer Registry, which lists prostate, breast, cervical, lung, and skin cancers and Kaposi sarcoma (often Aids-related) as the top cancers in the country.
Alarmingly, experts warn that cutting certain carbohydrates out of your diet, particularly whole grains and various fruits, actually increases your risk of developing cancer. Fruit and vegetables contain vitamins and thousands of phytonutrients and natural antioxidants that have anti-cancer properties, says Dr Louise van den Berg from the University of the Free State, founder of the Lipid Science Group. By excluding whole grains and certain fruit and vegetables, dieticians are also worried that people are not getting enough fibre, which is known to reduce the risk of colorectal cancers.
Noakes likes to portray himself as a revolutionary who is fighting against the dogma of Big Pharma and the big food industry, with his diet as a key weapon against most modern Western ailments that have been created by poor diets and pharmaceutical drugs. Yet his banting diet has also become a form of dogma that his many fans have embraced religiously without paying any serious thought to the long-term effects of a low-carb, high-fat diet.
An edited version of this story also appeared in the Daily Maverick