Serious doubts about value of low-carb diet
In the war on overweight and diabetes, many people are endeavouring to eat ‘less sugar’. Consequently, some people are led to assume that an extremely low-carb diet is to be preferred. In practice this means cutting out sources of starch such as bread, rice, potatoes and bananas. However, scientists have serious doubts about the value of doing so. Based on two international review articles published this week, professor Fred Brouns of Maastricht University (UM) concludes that reducing one’s intake of carbohydrates is fine, but a drastic reduction is best avoided.
Last year the village of Leende (in the Dutch province of North Brabant) attracted a great deal of attention because the village’s GPs had launched a campaign to minimise the amount of carbohydrates in people’s everyday diet. ‘It’s beyond dispute that minimising sugar intake will reduce the risk of overweight and diabetes’, says Brouns, emeritus professor of Innovation in Healthy Nutrition at Maastricht University. ‘But our research shows that adverse effects can arise as a result of following a low-carb diet (also referred to as a ketogenic diet). In particular, the low quantity of fibre and the high fat content of a low-carb diet can have detrimental effects on the intestinal flora.’ Many people find it difficult to persevere with a ketogenic diet, whereas a moderately adapted diet including 100–150 g of carbohydrates a day will be much easier to stick to. ‘There isn't actually any reliable data available at present on the health benefits of an extremely low-carb diet in the long run’, Brouns stresses. ‘Any attempts to promote such diets as “good for everyone” should be regarded in this light as well.’ Read more in Brouns's publication.
Brouns substantiates his own publication with a recent international study he was also involved in on dietary guidelines. An international team of scientists compared 11 sets of guidelines from 10 food authorities, including the WHO (World Health Organization) and the EFSA (European Food Safety Authority), as well as national food authorities in North America, Australia and Scandinavia. Without exception, the guidelines recommend drastically restricting intake of added sugars. However, not one of the authorities says anything about adopting a low-carb diet in order to achieve this. Indeed, in all cases studied the recommendation is to ensure that around 50% of daily energy intake comes from carbohydrates. According to Brouns, the quantity of carbohydrates could be reduced and the quantity of fat increased, resulting in a daily energy intake that comprises 40% of both types of nutrient. ‘It’s important in this respect to choose sources of carbohydrate that are high in fibre and high in unsaturated fat in particular. But the most effective way of preventing overweight and diabetes is to simultaneously modify multiple lifestyle factors. Besides healthy eating, this concerns such things as eating smaller amounts, quitting smoking, consuming alcohol in moderation and getting more exercise.’