Published in the international PLOS ONE journal yesterday, the SU study reviewed the result of 19 international scientific trials.
As part of these trials, about 3200 participants were placed either on low-carbohydrate or balanced weight loss diets. Studies lasted between three months and two years, and measured the diets’ impacts on risk factors related to heart disease, diabetes and cancer.
The study showed that fad banting diets that drastically restricted carbohydrate intake in favour of fats resulted in weight loss by restricting caloric intake – not by lowering the amount of carbohydrates consumed.
“This study shows that when the amount of energy consumed by people following the low carbohydrate and balanced diets was similar, there was no difference in weight loss,” says lead researcher, Dr Celeste Naude, from the Centre for Evidence-based Health Care at SU’s Faculty of Medicine and Health Sciences.
Based on these findings the Heart and Stroke Foundation South Africa, the Association for Dietetics in South Africa and other health groups are warning the public about the possible health risks associated with banting.
“Decades of research have shown the balanced diet to be safe and healthy in the long term, and along with a healthy lifestyle, is associated with a lower risk of heart disease, stroke, diabetes and certain cancers,” says Heart and Stroke Foundation South Africa CEO Dr Vash Munghal-Singh. “We do not have similar proof that a low-carbohydrate diet is safe and healthy in the long term, and some studies already point towards an increased risk of heart disease and death with low carbohydrate diets.”
“Chronic diseases like heart disease, stroke, cancer and diabetes develop over many years of exposure to risk factors,” she tells Health-e News. “The follow-up of the trials included in the review is no longer than two years, which is too short to provide an adequate picture of the long term risk of following a low carbohydrate diet.”
“Based on the current evidence we cannot recommend a low-carbohydrate diet to the public,” Munghal-Singh concludes.
Noakes stands by fad diet sweeping South Africa[quote float=”right”]“Based on the current evidence we cannot recommend a low-carbohydrate diet to the public”
Carbohydrates comprise at least 45 percent of a balanced diet. Protein should make up between 20 to 35 percent of daily calories with the reminder being derived from fats.
A balanced weight loss diet restricts energy intake in each of these categories, while maintaining the recommended balance between carbohydrates, protein and fat. International research has shown that a balanced weight loss diet ensures dieters meet nutrient requirements and reduces the risk of chronic diseases.
But Noakes argues that a high fat and protein diet has been known to reduce hunger leading to less food intake and thus less energy intake. He argues this diet is the easiest to follow.
“Unless the diet takes away hunger it will not produce the change in lifestyle necessary to sustain weight loss,” Noakes told Health-e News. “Low carb (diets) take away hunger in a way that no other diet does, that’s why it is the easiest diet to follow and the most effective.”
The Heart and Stroke Foundation South Africa admits that certain fat, particularly the mono- and polyunsaturated fats found in olive oil, fish and certain seeds and nuts, are beneficial to heart health.
But the foundation points out that the fats promoted in Noakes’s popular The Real Meal Revolution cookbook are mostly saturated fats like animal fats such as lard and butter, which have linked to high cholesterol and in turn increased heart disease and stroke risks.
The Association for Dietetics in South Africa also stressed that there is no “ideal” weight loss diet and that individual factors need to be considered when giving nutritional advice.
According to the association’s spokesperson Maryke Gallagher, effective weight loss strategies should take into account personalised factors like health status, physical activity, attitude towards food and stress levels.
“These factors will all affect the outcome of any dietary strategy,” Gallagher says.