WEIGHT OF EVIDENCE - JSE MAGAZINE

WEIGHT OF EVIDENCE

Is the ‘Tim Noakes diet’ all it is cracked up to be? Sure, it can help you lose weight, but it may not be good for your health in the long-term

WEIGHT OF EVIDENCE

Introduce the subject at a dinner party or over drinks with friends, and you’ll either be met with avid enthusiasm or a dismissive eye roll, but rarely indifference. Such is the polarising power of the greatest diet craze ever to sweep through SA – Banting, aka the ‘Tim Noakes’, low-carb/high-fat (LCHF) or ketogenic diet.

These names roughly describe the same eating plan, one that promotes a drastic reduction in carbohydrates (cutting out sugar, bread, pasta, rice, grains, potatoes, many fruits and certain vegetables) and a very high intake of fat, specifically animal fats.

In SA, the diet’s bible is The Real Meal Revolution, co-written by professor Tim Noakes, nutritionist Sally-Ann Creed, and chefs Jonno Proudfoot and David Grier. It has become one of the best-selling books of all time in the country (famously overtaking sales of 50 Shades of Grey), which is proof of its widespread popularity.

This diet is like no other. No kilojoule counting is required, although you are still advised to control the amount of food you eat if you want to lose weight. Even though you have to foreswear the comforting pleasures of carbs and sweets, you are ‘allowed’ to replace these with bacon, red meat, cream, butter, cheese and full-fat yoghurt. The linchpin of the concept is that you don’t feel deprived because the fat helps you feel fuller for longer, acting as a natural appetite suppressant. Adherents are (supposedly) more likely to stick to the diet in the long-term.

Noakes, the face of the diet in SA (it’s gaining in popularity in the UK and US too), assures us that saturated fat is not harmful in the least – it is carbs and sugar that have been making us overweight and diseased. So it is hardly surprising that ‘Banting’ is at the heart of what is perhaps SA’s greatest medical controversy.

Devotees have been active and extremely vocal on social media platforms about the diet’s health boons (rapid weight-loss in particular). But detractors – esteemed medical and nutritional experts among them – claim it is potentially dangerous, and that not enough is known about the long-term effects of the diet.

In 1863, a once-obese English undertaker, William Banting, published a booklet titled Letter on Corpulence, Addressed to the Public, in which he outlined both his failed and eventually successful dieting attempts. The eating plan that finally helped him shed the kilos involved a dramatic reduction in carb consumption. This method of weight-loss subsequently became fashionable at the time, popularising the question, ‘Do you Bant?’

Fast forward about 150 years and we find Noakes, an internationally renowned sports scientist and author of several lauded books, sitting at his computer, reading an email promoting a low-carb diet that promises rapid weight-loss without hunger. (Notably, he had previously recommended ‘carbo-loading’ for athletes in his book, The Lore of Running, but has since advised readers to ‘tear out’ the section on nutrition).

In an unusually receptive mood – having been diagnosed as pre-diabetic, feeling frustrated with his lagging energy levels and weight, despite following conventional dietary wisdom – he does not delete the dubious email but reads on, and does some research.

Noakes then adopted the LCHF diet (the modern incarnation of ‘Banting’), felt better almost immediately and had more energy for exercise. He began to proselytise what he believes to be the answer to weight-gain, diabetes, cancer and cardiovascular disease – too many carbohydrates and not enough saturated fat. He has since been labelled a junk scientist, conspiracy theorist, a fraud and irresponsible. However, to his fans – of which there are many – he is a hero who has helped them reclaim control of their weight; a maverick who has bravely challenged the status quo.

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‘Weight-loss needs to be successfully and safely maintained long-term. this is the biggest challenge’

No one disputes that cutting carbohydrates from your diet will result in weight-loss. Once the body stops receiving carbs, which is what it usually uses for energy after converting this food component to glucose, it ‘switches’ (in very simplistic terms) to using the body’s fat stores. It is then converted in the liver to fatty acids and ketone bodies through a process called a ‘ketosis’.

These can then be used for energy. Eating more fat, as the diet recommends, helps this process along. This is why, counter-intuitively, even if you’re eating large amounts of fat on the diet, you can still lose weight, provided your carb intake is minuscule. Obesity is a major risk factor for diabetes and heart disease, so losing weight, even via ketosis, can potentially be seen in a positive light (but if it is rapid, this comes with its own risks). However, do the ends justify the means? That depends. After all, smoking can also encourage weight-loss.

‘For immediate and quick weight-loss, the Banting diet seems to be beneficial,’ says Dr Chrisna Botha, biokineticist and senior lecturer in sports nutrition at North-West University. ‘But cutting out foods that pretty much form the basis of a diet is very hard to sustain, and people on this diet will most likely gain back the weight quicker than they lost it.’

She adds that cutting out an entire food group is a bad idea, as it may lead to deficiencies, especially in B vitamins and folate, of which a major source are whole grains. ‘My personal opinion is that this diet does not support healthy eating. Eating a variety of foods, including carbohydrates, has been proven to enhance health.’

In his debate with Noakes at the 2014 Franschhoek Literary Festival, professor Lionel Opie, one of the world’s foremost experts on heart disease, supported weight-loss via Banting. But he recommended switching to the Mediterranean diet once the weight-loss was achieved as it has a proven track record of improving the risk factors for cardiovascular disease and diabetes.

This sentiment is echoed by researchers Anel Schoonees (who is involved in a research project that includes the LCHF diet) and Celeste Naude, both from the Centre for Evidence-Based Health Care.

‘Weight-loss needs to be successfully and safely maintained [in the] long-term, and this is the biggest challenge. Once weight is lost, it is important for people to choose a way of eating that enables them to maintain the weight-loss; is not harmful over the long-term; is nutritionally sound [provides the nutrients needed]; and allows variety and flexibility so that it is easier to adhere to.

‘We do not know the long-term effects of eating little or no carbohydrates, and equally concerning is the inclusion of large amounts of unhealthy fats [especially saturated fats],’ said the researchers in a joint statement.

What is known is that saturated fat is implicated in cardiovascular disease. ‘There is consistent evidence that reducing saturated fat intake by decreasing and/or modifying dietary fat reduces the risk of cardiovascular events and reduces morbidity in people with heart disease.

‘The overarching message when it comes to the health values of various types of fats is that it is about substitution. If you remove one type of fat, what are you replacing it with?

‘Cutting back on saturated fat can be good for health if people replace saturated fat with healthy unsaturated fats, especially polyunsaturated fats. Removing saturated fat and replacing it with refined carbohydrates may be harmful,’ they said.

It is far more likely that the source of the Western world’s obesity problem is that we’re eating too much refined (an important distinction) carbohydrates and sugar, as well as fat. Heck, we’re eating too much. Period.

‘Eating a variety of healthy foods in moderate quantities and getting enough exercise is the key to living a healthy life,’ says Botha.

‘Obesity and disease are not caused by including bread, pasta or potatoes in our diet. They are caused by a lack of exercise and too much pastry, white bread and sugary drinks.

‘Another factor that plays a huge role is portion distortion. We now eat in one portion what is equal to two or three portions according to proper dietetic guidelines.’

By Rachel McGregor
Images: Ann Stratton/reneerhyner.com