Protein-rich diets best at keeping weight off
Published 25/11/2010 | 11:22
Protein-rich diets containing lots of lean meats, fish and egg - as popularised by the Atkins diet - are the best at keeping weight off, according to the world's largest study of its kind.
But dieters should also combine that with eating lots of wholegrain cereals and fresh fruit and vegetables, researchers have found.
People who stick to this approach can simply eat until they feel full and not put on weight, according to the Danish nutritionists. Their research is published in the New England Journal of Medicine today (THUR).
They asked 938 volunteers to go on a strict 800 calorie-a-day diet for two months. Then they split them up into five groups, each following a different low-fat diet aimed at maintaining their weight.
However, only those who stuck to the high protein, low glycemic index (GI) diet managed to stop putting any weight back on over the following six months. On average, the others put on 0.5kg (1.1lb). Those on the worst-performing regime - a low protein, high GI diet - put on almost 2kg (4.4lb).
Prof Arne Astrup of Copenhagen University, who headed the pan-European Diogenes study, explained why the high protein, low GI diet worked best.
He said: "It's simply due to satiety - of what gives a feeling of more fullness."
Protein-rich foods resulted in "a greater release of satiety hormones" than othertypes, he explained.
"You simply stop eating after you have consumed fewer calories than with the other diets."
But consuming low GI carbohydrates was also important.
These are foods like wholegrain cereals that the body takes longer to digest, resulting in blood glucose levels rising and dropping more gradually.
These tend to suppress appetite for longer, in contrast to high GI foods like mashed or baked potato or sugary cereals, which cause rapid rises and falls in blood sugar levels.
The researchers recommended lean meat, poultry, fish, eggs, low-fat dairy products, beans and nuts as good sources of protein.
Besides wholegrain cereals, they also said pasta cooked 'al dente', new potatoes - preferably cooled down - and basmati rice were good sources of low GI carbohydrates.
Although the study involved obese adults, with an average body mass index of 34, Prof Astrup said the principles behind the diet applied "absolutely" to people who were healthy or only slighty overweight.
The Atkins diet, which millions tried at its peak in 2004 following praise from personalities including the actress Jennifer Aniston, is itself based on the principle that high protein foods make one feel full sooner.
But Prof Astrup emphasised: "This diet is far away from Atkins."
While 50 per cent of calories come from protein under Atkins, he said with their diet the percentage was just 23.
And while under 'low-carb' Atkins as little as 10 per cent of calories come from carbohydrates, in their diet the figure was 45 per cent.
Thomas Meinart Larsen, who also worked on the study, explained why new potatoes were best served cold.
"This is due to the chemical structure of the carbohydrates when cooled down," he said. "Therefore they are broken down more slowly in the intestines."