There's never a shortage of diets promising to help us shed kilos but the real holy grail of weight loss is nailing a way of eating that keeps the weight from creeping back on. But scientists from the University of Copenhagen believe they have an answer: a higher protein/ lower carbohydrate pattern of eating they've called the World's Best Diet.
A name like this has a lot to live up to but this eating plan, published as a book in Denmark in 2012, is based on credible research – a large European study known as the Diogenes Diet that compared five different diets to see which worked best at keeping weight off.
A total of 773 adults who'd already lost an average of 11 kilos were assigned to one of five diets each based on a different combination of protein and carbs - some were lower in carbs and higher in protein and vice versa. Some diets included high GI carbs- meaning the 'fast', often more refined carbs that raise and lower blood sugar rapidly; others had slower burning low GI carbs that raise and lower blood sugar more slowly. And the winner? The low GI carb and high protein combo. The people on this diet not only kept the weight off during the six months of the study but they also continued to lose weight too.
This way of eating works because both protein and low GI carbs help us produce more of the satiety hormones that keep us feeling full, explains Jennie Brand-Miller, Professor of Human Nutrition at the University of Sydney's Charles Perkins Centre.
Brand-Miller, co-author of the Australian edition of World's Best Diet, believes we've often missed out on the filling power of these foods - partly because of the 'eat more carbs' message but also because so many carbohydrates are very refined.
"The advice over the last 30 years has put too much emphasis on carbohydrates and neglected the satiating effect of protein – we took it for granted that Australians were getting enough protein," she says. "At the same time the carbohydrates we were eating were getting fluffier."
There are no fluffy carbs in this diet. Instead it's based on fresh vegetables, lean protein sources like fish, poultry, legumes, nuts and dairy foods and dense, grainy foods like rye bread, pumpernickel and barley - the book's recipe for rye porridge with apple and hazelnuts is the polar opposite of lightweight breakfast cereal.
The reason these robust carbs are more filling than their more refined cousins like white bread isn't just that they keep blood sugar levels steadier, Brand-Miller explains. They also stimulate cells in the gut that produce one of the satiety hormones we need to feel full. These cells are located deep down in the gut – a place that rapidly digested carbs never reach because they're digested in the upper half of the gut, Brand Miller explains.
"This explains why we still feel hungry after we've eaten fluffy white rice," she says.
But while the World's Best Diet is higher in protein and lower in carbs it's no radical diet. The idea is to modestly lower the carbohydrate content of the diet and modestly increase the protein content to give a ratio of around 2:1 in favour of carbs, says Brand- Miller explaining that a typical Australian diet is generally higher in carbohydrates with a ratio as high as 4:1
Another reason why increasing protein is helpful is because it helps the body's basal metabolic rate - the rate at which it burns kilojoules - to stay higher, she adds.
One concern about higher protein diets has been the long-term effects on health, especially with eating plans high in animal foods. But after a year, the people taking part in the Diogenes study, who were eating the high protein low GI carb combination, 'had healthier levels of inflammatory markers in the blood - a positive sign that their risk of heart disease and other chronic diseases had lowered.'
Brand-Miller is now testing whether the diet reduces the risk of type 2 diabetes. If you're overweight and have a family history of type 2 diabetes, you may be eligible to participate (go to: preview.ning.com/sydney).
World's Best Diet by Arne Astrup, Christian Bitz, Jennie Brand-Miller and Susan B. Roberts is published by Penguin, rrp $35.00.