Media Release

Wednesday 18 April, 2007

More wholegrains means smaller waistline

A NEW Australian study has found that people who want to lose weight or avoid weight gain should be advised to consume plenty of wholegrain cereals and legumes while controlling overall energy intake.

After assessing 556 studies published in the scientific literature during the last 25 years, the researchers found a diet high in wholegrains has a strong link with lower body mass index (BMI), smaller waist circumference and a reduced risk of being overweight.

They also found that a diet high in wholegrains and legumes can actually help reduce weight gain, and that significant weight loss is achievable with energy controlled diets that are high in cereals and legumes.

The National Centre of Excellence in Functional Foods at the University of Wollongong conducted the review of international scientific literature to determine the role of grains and legumes in the prevention and management of overweight and obesity.

Study leader Associate Professor Peter Williams said the findings will be of interest to Australians who may be concerned that high intakes of grains such as cereals, bread, rice and pasta could lead to weight gain.

“One of the most popular diet myths in recent times is that grains, and the carbohydrates they contain, provide excess energy to the body and are therefore fattening,” Prof Williams said. “So we set out to establish what the science actually says about that question.”

Professor Williams’ review of the literature found this belief about grain foods and weight gain is not supported by scientific evidence. In fact, the opposite was found to be true - that a high intake of grain-based foods is linked with healthy weight management. Those most successful at maintaining weight loss follow a low fat, high carbohydrate diet.

“The vast majority of Australians should be enjoying a diet high in wholegrain foods because grains and wholegrain foods not only contribute to good overall health, the evidence is they also help maintain a healthy weight,” Prof Williams said.

How do grains help maintain healthy weight?

A number of studies in the research review found that higher grain intakes were associated with lower total energy intakes, likely due to the higher fibre content of diets high in wholegrains and legumes.

Professor Williams said there are a number of ways in which wholegrain foods and fibre can affect energy balance, including energy density, palatability, hormonal effects and the effect of satiety or ‘fullness’ caused by these foods.

“The generally lower GI values of diets high in wholegrains and legumes may be another important factor as they create a feeling of fullness and may also slow starch digestion which helps lower insulin levels, which are implicated in being overweight,” Professor Williams said.

“It’s clear from the research that, regardless of the exact mechanism or combination of factors involved, significant weight loss is achievable with energy controlled diets that are high in cereals and legumes,” Professor Williams said.

Benefits to health

In addition to helping maintain healthy body weight, research studies show strong evidence that grains and legumes are protective against a number of other diseases such as heart disease and diabetes.

Ms Trish Griffiths, Accredited Practising Dietitian and Executive Manager of Go Grains Health and Nutrition, said cereal grains are a rich source of many essential nutrients.

“Clinical research shows that grain-based foods are an excellent source of carbohydrate, dietary fibre and protein, and are a good source of many B-group vitamins, vitamin E, and a number of minerals – especially iron, zinc, magnesium and phosphorous,” Ms Griffiths said.

“National dietary guidelines in Australia, and around the world, recommend consumption of grain foods as the basis of a healthy diet, and increasingly there has been emphasis placed on increasing the proportion of wholegrains.”

“This is consistent with public health dietary recommendations to make bread and cereals the foundation of a healthy diet and to emphasise wholegrain in this context,” she said.

Professor Williams said the risk of obesity may be reduced by eating more wholegrain, high-fibre, and low GI grain foods, with at least three serves a day being the right amount to have an effect on obesity.

“The average intake of wholegrains in the US is less than one serving a day, and less than 10 per cent of Americans consume the recommended minimum three servings per day,“ Professor Williams said. “The situation is pretty much the same in Australia, so there’s substantial opportunity to improve the grain and legume intake of most people,” he said.

Literature Review –

Cereal grains, legumes, and weight management: a comprehensive review of the scientific evidence.