Low fat diets are just as effective as the controversial Atkins diet when it comes to losing weight over the long term, according a study.
The Atkins diet involves cutting down on carbohydrates
Research by doctors in Denmark has found that people on Atkins-style low carbohydrate diets tend to lose more weight in the first six months.
But they said weight loss for both groups is similar after 12 months.
Writing in The Lancet, they said people on Atkins may lose weight because they are bored eating the same foods.
Professor Arne Astrup and colleagues at RVA University in Copenhagen looked at three studies carried out in the past two years.
In the first study, 132 severely obese people were put on either the low-carbohydrate diet or a low fat diet.
After six months, those on Atkins had lost on average 3.9kg more than those on the low fat diet. But after 12 months, both groups had lost the same amount of weight.
In the second study, 53 obese women were put on either the Atkins diet or a low fat diet.
After six months, those who had cut out most carbohydrates had lost 8.5kg compared to those who ate low fat foods who lost 3.9kg on average.
In the third study, 63 people were put on either the Atkins diet or a low calorie diet.
After six months, those on Atkins had lost twice as much weight as those who had reduced their calorie intake. But after 12 months, there was little difference between the groups.
Professor Astrup, who also works as a medical adviser for Weight Watchers, said boredom may help people on the Atkins diet to lose weight.
"The monotony and simplicity of the diet could inhibit appetite and food intake."
The study found more evidence to suggest that reducing carbohydrates may reduce the risks of heart disease by cutting bad cholesterol.
However, the researchers warned that cutting out fruit, vegetables, whole-grain bread and cereals may actually increase the risk of heart disease and cancer by denying the body the positive properties of these food groups.
They said that while low carbohydrate diets appeared to be safe in the short term, people who want to keep weight off should go on low fat diets.
"The most solid current recommendation for people who want to lose weight and keep weight off is a permanent switch to a diet reduced in calories and fat in combination with physical activity," they said.