What's in our food: Supersizing the nation's fat intake

In the final of our week-long series on food safety, Herald health reporter Martin Johnston examines our love affair with takeaways - and exactly why they can be bad for you.

The series has covered all the main food groupings. As well as takeaways, it examines the pros and cons of fruit and vegetables, meat, dairy products, and processed foods such as bread, biscuits and cereals.

We eat it on the beach, we eat it in the car, we eat it at home.

Crispy, golden, deep-fried fish and chips is deeply embedded as one of New Zealanders' favourite fast foods.

Although other takeaway foods are catching up fast (a Herald-DigiPoll survey last Saturday showed Asian food of all kinds marginally ahead) New Zealanders eat 7 million serves of hot chips every week - around 110,000 tonnes a year.

Spending on takeaway food in general passed $220 million in the three months to June 30 last year. That's a leap of almost 50 per cent since 1998 and nearly equal to a $4.45 Big Mac burger once a week for every adult, child and baby.

We keep eating junk food despite regular warnings that it is well named.

"Your intake of protective substances would be minimal from fish and chips, compared with a meal with colourful vegetables," said Christine Cook, a dietitian at the Auckland Regional Public Health Service.

And that's not to mention the biggest worries about fast food: the commonly-high levels of saturated fats (bad for the waistline and the heart) and the high energy density (packing in more calories than you may need).

These are the main ways that takeaway food affects our health for the worse.

Energy The main sources of dietary energy are protein, fats and carbohydrates, comprising 15.5, 35 and 46 per cent respectively of the New Zealand diet.

Fast foods, along with relaxing in front of the TV instead of walking the dog, are often blamed for a large share of the international rise in obesity, but the association between fast food and weight gain found in some surveys is not conclusive proof.

A study by Dr Shanthy Bowman and Dr Bryan Vinyard in the Journal of the American College of Nutrition reported a "small" association. Those who ate fast food were about 30 per cent more likely to be overweight that those who did not eat it.

Obesity increases the risk of heart disease, stroke, type 2 diabetes and cancer.

The percentage of obese adults in New Zealand has grown sharply - from 11 per cent in 1989 to 17 per cent in 1997. For children, the figure stood at 9.8 per cent in the first national survey, published last year.

In 1997, daily adult energy intakes were 11,600 kilojoules (kJ) for men and 7700 for women. These appear to have increased about 450kJ since 1989, but the researchers say changes in their survey methods make valid comparisons impossible, although others expect an increase has occurred.

The United States is not hampered in this way and researchers there report an increase of more than 837kJ from 1978 to 1996.

The concept of "energy density" has been used to show how fast foods, which are mostly high in energy for their weight and bulk, are likely to trick our bodies into eating more than we need.

British nutrition experts Professor Andrew Prentice and Dr Susan Jebb say in the journal Obesity Reviews that humans tend to consume a similar bulk of food with little reference to its energy density.

Their experiments have shown that people fed energy-dense meals tended to consume too much energy because these foods undermined the processes regulating appetite.

They "failed to adequately compensate for increased energy density by reducing the weight of food eaten".

They compared typical fast foods with women's diets in Britain and in a rural subsistence farming community in West Africa.

The energy density of the fast foods was almost 1.7 times higher than the average British woman's diet and 2.5 times the African level.

To get the right amount of energy, the Africans needed to eat around 2kg of food a day, while the Britons needed 1.3kg. But if the whole diet was at the high-energy densities common in fast foods, people would have to cut back to 700g to 800g a day to avoid exceeding the average recommended intake for the moderately active.

The researchers argue that children and young adolescents may be at greatest risk from energy-dense fast foods as they have not developed the conscious dietary restraint needed "by anyone wanting to stay lean in the modern environment".

They recommend vendors give up manipulative pricing and pressure selling of extra or larger items.

American researchers Lisa Young and Marion Nestle suggest that bigger portions of foods, from muffins to McDonald's chips, could be linked to rising obesity.

"In the mid-1950s, McDonald's offered only one size of french fries; that size is now considered 'small' and is one third the weight of the largest size available in 2001," they wrote in the American Journal of Public Health.

They go on to discuss the even larger "supersize", which became the subject of the movie Supersize Me. The McDonald's chain in the US said in March that it was withdrawing supersize fries and drinks from its menu but the move was nothing to do with the movie, which it criticised.

McDonald's communication manager in New Zealand, Liam Jeory, said its restaurants had never offered the "huge portions".

But many practise "upsizing", as do rival burger shops.

At one Burger King outlet the Herald visited, upsizing involves asking a customer who orders a burger whether he or she would like just the burger, or a meal (which includes a drink and fries).

If the customer opts for a regular-sized meal, the salesperson then asks if they want to upsize to a large meal (same burger, large fries, large drink).

At McDonald's the price of a Big Mac Combo (burger, fries and drink) goes from $6.65 for a medium to $7.25 for a large - just 60c more, but up to 700 more kilojoules of energy.

Micro-nutrients

The flip-side of a fast-food diet is the lower levels of essential nutrients being consumed.

The Shanthy-Vinyard study found that those eating fast food consumed significantly less carotene, vitamin A, vitamin C, calcium, magnesium, fruit and non-starchy vegetables.

This is why Christine Cook's public health team feel comfortable encouraging people to eat stir-fry, Middle Eastern kebabs, salad sandwiches and roasts. They all contain colourful vegetables such as lettuce, tomato, peas and carrots.

She welcomed the move by McDonald's and other chains to introduce salads, but said they were too light to be a meal.

Jeory said McDonald's salads were hugely popular but many customers wanted them to contain, for example, more chicken - "more protein to make it more of a satisfying meal". The menu would soon be expanded to cater for this. Fats As part of a "healthy kai" project in South Auckland, Public Health has had many fast foods tested. Mangere stir-fries had one of the lowest fat levels, averaging 6 per cent, but Otara's curries averaged 10 per cent and the worst was 20 per cent. Some curries are loaded with cream or coconut cream.

"Curries are out in Otara," Cook said.

Focusing on reducing fat intake, the project encourages grilled fish over fried, rice and stir-fry over fried chicken, sandwiches over pies and iced buns over cakes.

The Heart Foundation is equally concerned about fat intake. Because New Zealanders eat so many hot chips, the foundation has been trying since 1997 to encourage chip sellers to make them healthier by reducing their fat content and using better fats.

The methods are simple: use thick, straight-cut chips, which absorb less fat than crinkle-cuts or shoestrings; cook at 180C; drain and shake the cooked chips correctly. Done properly, this can cut fat content by 20 per cent. The foundation says if all chips conformed, 2500 tonnes of fat would be removed from the national diet annually - "the equivalent of 574 elephants".

The national average fat content is 11.5 per cent, but the winner and regional finalists in the 2002 Best Chip Shop competition achieved less than 10 per cent.

The relationship between fat and disease is not straightforward. While consuming more energy (from fat and other food components) than is used can lead to weight gain, the type of fat is also important.

Saturated fat and trans fatty acids are associated with increased levels of bad cholesterol in the blood - a risk factor for heart disease - while mono and poly-unsaturated fats can lower cholesterol.

The foundation recommends using frying oils that are less than 20 per cent saturated plus trans fatty acids, such as sunflower oil, high in oleic acid, or canola oil. If the canola comes in solid blocks it is probably relatively high in trans fats.

It also warns consumers about outlets promoting their use of "cholesterol free oil" or "vegetable oil". This may be palm oil or a derivative which contains no cholesterol but has a high level of saturated fat.

A foundation-Auckland University survey found that 11 per cent of operators used palm oil and 82 per cent used beef tallow. Both are high in saturated fat and are "not nutritionally acceptable".

They are often preferred by operators because they are relatively cheap and last longer.

McDonald's changed last year from beef tallow, which contained 55 per cent saturated fat, to a blend of high-oleic sunflower oil and liquid canola oil.

Jeory said it was a complex switch which had added more than $1 million a year to the chain's bills.Salt Common salt contains sodium. High sodium intake is linked to high blood pressure, which is linked to increased risk of stroke and heart disease.

The average daily intake of salt in New Zealand is about 9g, nearly twice the recommended maximum of less than 5g. About 75 per cent of sodium intake comes from salt - and other flavour enhancers like monosodium glutamate (MSG) - added to manufactured foods ranging from supermarket white bread to chips from a suburban takeaway.

Many fast foods contain plenty of sodium, but chips are not necessarily the saltiest and you can ask for them to have less or no salt. Some operators provide sachet salt.

Food composition tables compiled by the Institute for Crop and Food Research reveal some of the highest sodium concentrations are in bacon burgers, some fried chicken pieces, battered and fried saveloys, pizzas, sausage rolls and some Asian meals.

Food poisoning

Campylobacter, salmonella and listeria can cause illness and even death. New Zealand has far higher rates of these diseases than comparable countries.

Its food-borne disease rate is the highest in the developed world. More than 14,500 cases of campylobacter illness were notified last year - the actual number of cases is thought to be five times higher - and in 2002 the per-capita rate was nearly nine times higher than Canada's.

Takeaways present numerous opportunities for food poisoning, especially staff touching ready-to-eat items after handling raw meat.

Public health physician Greg Simmons said about half of all reported food poisoning outbreaks in New Zealand might be associated with commercial food premises, including fast-food outlets.

In a bid to improve hygiene, the Food Safety Authority has proposed rewriting regulations so all food premises would have a food control plan. Currently, big food manufacturers have such plans, but takeaway bars and food stalls generally do not. Simmons said McDonald's and other big chains tended to have safe practices.

Some councils require staff at food businesses to be trained in safe food handling but others do not.

So after limiting your fast food intake, checking the cooking fat and making sure you get a range of coloured vegetables, it may pay to watch that your local burger maker washes his or her hands before assembling your burger.