Food pyramid under reconstruction

The information is as abundant, and as contradictory, as a Valentines smorgasbord. Newspapers, magazines and TV ads daily feed our craving for the latest on antioxidants, free radicals, low and high GI, good fats, bad fats, calories or kilojoules, foods that stave off cancer, foods that cause cancer.

No sooner are we throwing away the cereal and pasta packets than we're restocking with porridge and bread and swearing off red meat.

The high-protein Atkins Diet may be on the way out but it achieved one thing: prompting health agencies to rewrite the rules on healthy nutrition. A revised food pyramid was launched in the United States in May and the New Zealand Heart Foundation is leading a review of food guide models here.

The existing pyramid is outdated and misleading, this month's Dietetic Association conference was told.

Diets based on the pyramid may not provide enough fat-soluble nutrients such as omega 3, omega 6, vitamin D and vitamin E, visiting nutritionist Bill Shrapnel said. The oils promoted heart and circulatory health, vitamin D was necessary for bone health and vitamin E was an important antioxidant, the online FoodWorks News reported.

The answer was for food guides to include a new food group called healthy fats including margarines, vegetable oils, nuts and seeds.

The Heart Foundation, which introduced the now-ancient food pyramid, has completed scoping work on what is needed in a new national food guide and is awaiting the Ministry of Health's decision on the next steps.

An easy-to-follow guide is seen as a powerful weapon in the fight against poor nutrition and obesity - though agencies stress it cannot do the job on its own.

But ending the confusion over what's good for us is proving as challenging as dieting at an all-you-can-eat buffet. For starters, how do you define junk food? What place high-starch carbohydrates? Should it include serving size data? What about alcohol?

"Nutrition science is quite new," says Celia Murphy of the Obesity Action Coalition. "We're learning more as we go.

"People think we change our minds every day but it's not just health people being fickle. It's a long slow process trying to figure out what's best and what's not."

Despite the glut of conflicting reports and fads, the basic nutrition rules still stand, says Carolyn Watts, past chairwoman of Agencies for Nutrition Action.

"There's a lot of noise coming from one-off studies, the food industry and the weight-loss industry, but the basic messages of nutritionists haven't changed over the years."

The rules are included in the Ministry of Health's national nutrition guidelines, which suggest we eat a variety each day from the four main food groups (see table).

Beyond that, nutrition gets tricky. In the US, the new internet-based food guide MyPyramid allows people to build a personalised food guide model based on factors such as weight, gender and age. But it has been criticised as overly complicated and critics doubt poorer people most at risk of obesity will use it. For one thing, the recommended foods such as chicken and fresh fruit and vegetables are comparatively expensive.

The new, colour-coded model makes few changes to the food groupings but tweaks a few things: rapidly digested carbohydrates like white bread, potatoes and pasta are shifted from the base of the pyramid to the top; "good" monounsaturated and polyunsaturated fats and oils like omega 3 are separated from "bad" animal fats such as butter.

Public health critics say the influence of the all-powerful food industry means the new pyramid still permits a diet high in saturated fats and sugar. Red meat, for instance, is not separated from fish or chicken.

In this country, the battle with food producers is still to come. But milk, butter, cheese and meat - staples of our GDP but high in saturated fats - can expect scrutiny for their links to heart disease.

Consultation has also raised questions about developing a single model in an increasingly multicultural society.

Foundation dietitian David Roberts says there's general agreement that the model should have a common science base. It has recommended a set of decision-making principles - one being that public health principles take precedence over "commercial imperatives".

Although there's support for a single guide, the foundation sees scope for variations to cater for different groups. There are ethnic takes on the food pyramid already, such as Maori health provider Te Hotu Manawa Maori's food kete and Pacific Heartbeat's Eat for Health. Consultation with consumers is one of the next steps.

"We're not precious about holding on to a food guide model if that's not what consumers want."

Roberts says the model itself may be less important than the messages that surround it. "A model that succeeds in creating change is one that's supported by a wider campaign in food and nutrition - it may just be the catalyst for change."

"There are simple things we can do," he says, "like switching from butter to a spread, from full fat to low fat milk, eating more fruit and vegetables and whole grains, avoiding too much animal fats.

"But you would be confused if you believed everything you read on the internet and in the media."