New international dietary guidelines released

What we eat, and the excess body weight we carry, has overtaken smoking as the most important preventable cause of disease, prompting the World Health Organization (WHO) to release updated dietary advice involving fat and carbohydrate intake.

The WHO recommends that adults limit fat intake to 30% of their total energy intake, with no more than 10% of total energy coming from saturated fats and less than 1% coming from trans fats.

The recommendation to restrict total fat intake is intended to help prevent excessive weight gain, as fat provides more than twice as much energy per gram than protein or carbohydrate.

Scientists from the Healthier Lives–He Oranga Hauora National Science Challenge, Professor Sir Jim Mann and Dr Andrew Reynolds, have contributed to research informing the new WHO dietary guidelines, which incorporate the most up-to-date international evidence.

“WHO endorsement of advice to reduce total and saturated fat is helpful, as not only are Kiwis eating more fat than recommended (an average of 35% total and 15% saturated fat) but also because some popular diets which include radical restriction of carbohydrate suggest or imply that there is no need for any limitation on fat intake,” said Healthier Lives Director Mann.

Limiting saturated fat, which is found in meats, dairy and coconut products, is important for reducing the risk of heart disease.

Earlier this year Reynolds published a WHO-commissioned meta-analysis on the health effects of replacing saturated and trans fats with unsaturated fats.

“Replacing saturated fats with mono and poly unsaturated fats, like those found in vegetable oils, nuts and seeds, and avocados, was associated with lower rates of heart disease,” Reynolds said.

The evidence shows that a wide range of carbohydrate intake is compatible with a healthy diet (40–70% of our total energy intake), but it is the quality of the carbohydrate that is of key importance.

The new WHO advice recommends that carbohydrates should come primarily from whole grains, vegetables, whole fruits and pulses. Pulses include foods such as kidney beans, chickpeas and lentils.

“There are three main groups of dietary carbohydrate: sugars, starch and fibre. Each of these groups has a different relationship to our health, so just talking about increasing or decreasing carbs is not that useful. Instead we should be talking about reducing sugar intakes and increasing fibre intakes,” Reynolds said.

WHO recommends that adults consume at least 25 grams per day of naturally occurring dietary fibre from their food.

“Our research has shown that the potential of dietary fibre to reduce the risk of common diseases such as type 2 diabetes, coronary heart disease and colorectal cancer is much greater than had earlier been appreciated. For example, an 8 gram per day increase in dietary fibre is associated with a 15% reduction in the risk of developing type 2 diabetes or dying from heart disease,” Reynolds said.

Mann said that having clear and evidence-based dietary advice is important, but further steps are needed to make these recommendations accessible to everyone.

Image credit: iStockphoto.com/YelenaYemchuk