The Centre for Evidence-based Health Care at Stellenbosch Universityin South Africa dominated South African news after publication of its study findings in PLOS ONE debunking claims that low carbohydrate diets result in more weight loss.
The study, with LSTM professor and Consortium Director Paul Garner as co-author, pooled the results of 19 clinical trials that met specific criteria and measured weight loss and heart disease risk factors such as blood cholesterol levels. This study included 3,209 overweight and obese participants, some with diabetes.
“It 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 after 3 to 6 months and after 1 to 2 years in those with and without diabetes", said lead researcher Dr Celeste Naudé from the Centre for Evidence-based Health Care at Stellenbosch University's Faculty of Medicine and Health Sciences, in a supporting press release.
The Centre for Evidence Based Health Care and the DfID funded Consortium conducted the systematic review in response to a request from the Heart and Stroke Foundation South Africa. Its objective was to study claims that low carbohydrate diets are more effective for losing weight compared to balanced weight loss diets and in addition improve heart risk and prevent of even cure diabetes.
“In the trials that compared the amount of energy consumed by participants following a low carbohydrate diet and those following the balanced diet, there was no difference in weight loss after 3 to 6 months and after 1 to 2 years in participants with and without diabetes”, said Professor Jimmy Volmink, co-author and Dean of the Faculty.
The diet pattern promoted by low carbohydrate diets differs from balanced diets. To achieve low carbohydrate intake these diets prescribe avoidance of all grains, cereals and legumes, restriction of many vegetable types and most fruits, and promotion of large amounts of fat, especially animal fats and other sources of saturated fats. At the extreme these diets can contain around 80% fat.
A balanced weight loss diet, however, limits energy intake by guiding portion sizes and food choices, but maintains the balance between the recommended ranges of carbohydrates, protein and fat. Studies over long time periods show that this diet pattern reduces the risk of disease and supports intakes that meet nutrient requirements.
After publication in PLOS ONE and the press release the study outcomes have dominated South African media leading to intense debates between proponents and opponents of the reviewed low carbohydrate diets.