Low-carb diets hold sway short-term
Cutting sugar and adding fat to our daily diets is more effective for losing weight short-term than maintaining a low-fat diet.
Low-carb diets, which focus on shunning carbohydrates while gobbling down proteins and fats, have been criticised by some nutritionists as unhealthy and potentially risky methods of losing weight.
But this kind of diet can be effective for shedding kilos short-term, concludes a group of experts who have been tasked by the Swedish state to assess research on food and obesity.
Their findings were recently published in Mat vid fetma, a report from the Swedish Council on Health Technology Assessment (SBU).
No long-term differences
“The analysis showed that low-carbohydrate diets, when compared to low-fat diets, yield more weight reduction and a marginally greater increase in HDL cholesterol without any negative impacts on LDL cholesterol,” say the researchers.
HDL cholesterol [high-density lipoprotein] is known as ‘good cholesterol’, whereas LDL cholesterol [low-density] is the bad boy. By short-term weight loss the scientists mean around six months.
But they insist that they found no differences between various diet regimes over the long run, whether these were low-carb, low-fat, high-protein, Mediterranean fare, low-glycemic or foods with a high share of monosaturated fats.
The report concludes that obese people run a lower risk of cardiovascular disease and premature death if they receive intensive counselling about Mediterranean diets, rather than advice about diets with a low fat content.
Studied over 16,000 reports
The research group examined upwards of 16,000 scientific studies to get an updated perspective on current nutrition research. But only 68 studies were considered good enough to provide the basis for future recommendations about healthy diets.
“One reason that low-fat diets have been a mainstay of recommendations for decades on weight loss or avoiding weight gain is their low energy content per unit of weight,” write the researchers.
Emotionally charged debate
However, more recent research has provided better insight into the effects of diets. This is particularly true for comparative studies of different diets and an increased emphasis on eating low-carb foods.
“An emotionally charged and polarised debate has arisen in which advocates of low carbohydrate contents and often high fat content have criticised the low-fat diet that has been recommended since the 1970s,” the report says.
Some of the studies they reviewed focused on the potential of increased cardiovascular disease from various diets.
But these did not focus on low-carb diets, and the more generalised studies were rather weak from a scientific stance. So the group of experts mustered by SBU couldn’t arrive at any conclusion about links between low-carb diets and cardiovascular disorders.
Choice of diet isn’t the most important
“The report shows there are many ways of losing weight. It’s important to discern between nutritional advice and dieting, and general advice on how to eat to maintain good health in the long run,” comments Arnhild Haga Rimestad, a dietician and senior adviser at the Norwegian Directorate of Public Health.
“The report confirms what we already knew – the main thing is to stick to the diet you choose, rather than choosing the right diet. But it doesn’t answer the question of which diet is best for obese or overweight people over the long run.”
“What we do know is that steadily more research shows that a diet along the lines recommended in Norway, eating more fruit and vegetables, fish, whole-grain products and breads, reducing salt consumption and being physically active are ways of reducing the risk of cardiovascular disease, cancer and diabetes,” says Rimestad.
Translated by: Glenn Ostling