A report published in today’s Guardian says that low-carb and Mediterranean* diets are better than low-fat plans for losing weight.
The news article by health editor Sarah Boseley also says the research (published in the Lancet Diabetes and Endocrinology journal) has found that in the long-term no diet worked particularly well.
The study involved more than 68,000 people and looked at 53 long-term studies that had been carried out since 1960 comparing diets. It was funded by the National Institutes of Health and the American Diabetes Association.
Lead author of the Lancet piece, Dr Deirdre Tobias from Brigham and Women’s Hospital and Harvard medical school, Boston, said the research showed there was no good evidence for recommending low-fat diets, as their “robust evidence” showed that simply reducing fat intake would not naturally lead to weight loss.
Low-fat diets gained popularity in the latter half of the 20th century because it was assumed that a low-fat diet would decrease the overall calories of the diet, as fat contains more than twice the calories per gram than carbohydrates.
The popularity of low-fat diets led to a huge expansion of low-fat foods on offer, such as low-fat yoghurts, spreads, ready meals and more.
Cutting fat “wrong”
The analysis in the Lancet says the advice to cut out fat is wrong.
The researchers did find that although low-carb and Mediterranean diets worked better, no diets worked particularly well in the long run (more than a year) for weight loss. In the trials, people on the low-carb diets only lost 2.2lbs or 1kg more, on average, than people on low-fat diets. The overall average weight loss after a year was 3.75kgs.
Keith Hall, of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, US, said one main reason why people failed to lose more weight was probably that they had given up well before the year was over.
More research needed
He said that much more research on how to help people lose weight and keep it off, a view echoed in the Guardian piece by Naveed Sattar, professor of metabolic medicine at the University of Glasgow.
Dr Tobias said that small amounts of weight loss were helpful to people with conditions such as diabetes, but that what was needed was a stronger intervention than one that helped people lose a few pounds here and there.
The Diabetes Diet says – “Our diet is primarily aimed at helping people gain good control over their blood sugar levels, and the best way to do this is to limit your carbohydrate intake. Weight loss isn’t the main goal of the Diabetes Diet, but people often find that they do lose weight on a low carb diet because the higher intake of protein and fats is more satiating.
“In addition, our diet promotes real food – meat, fish, eggs, nuts, dairy products, vegetables and more – rather than ready meals, snacks and processed foods which are common on low-fat diets, and that use all kinds of nasty additives and ingredients.”
*The Mediterranean diet, according to the Mayo Clinic, emphasises eating mainly plant-based foods, such as fruit and vegetables, whole grains, legumes and nuts, using olive oil, herbs and spices, eating fish and limiting red meat to only a few times a month.