Five kitchen rules: the healthiest, leanest ways to cook

We all love a bit of crunch, but the health risks of charred foods are alarming. Photo: Getty Images

• Fast moves to slow down ageing

Sometimes it's not so much the food we eat that makes us fat and sick, but how we cook it.

When researchers at Duke University in the United States looked at the food habits and weight of 4646 British children recently they concluded that potato chips were one of the most obesity-promoting foods, closely followed by crumbed chicken, and fish and hot chips.

Yet, as the researchers pointed out, there's nothing wrong with potatoes, poultry, and fish themselves – the trouble starts when we plunge them into a bath of sizzling oil. 

The extra kilojoules aren't the only health issue with deep frying. There's also the formation of potentially harmful chemicals created by frying, grilling, roasting and baking certain foods at high temperatures. 

"One problem is acrylamide, a chemical that can be formed when starchy foods such as potatoes, breads and biscuits have been fried, roasted, baked or toasted at high temperatures causing browning," Sydney-based dietitian Caroline Trickey​ says. "Acrylamide is considered to be probably cancer-causing according to the World Health Organisation's International Agency for Research on Cancer."

In its Acrylamide and Food fact sheet, Food Standards Australia New Zealand suggests it's "prudent to reduce our exposure to acrylamide in food".

While the odd packet of chips or Anzac bikkies is no big deal, it's not hard to consume a lot of baked browned foods on a regular diet of well-browned toast and toasted cereal for breakfast, a toasted sandwich for lunch with some crunchy snack foods or muesli bars thrown in, Trickey says.

"It's about how much of these foods you eat and what else you're eating – some people eat a lot of foods like this but  little or no fruit and vegetables. But a diet rich in vegetables and fruit will help protect against the effects of acrylamide. There's a difference between eating fried bacon with a piece of brown toast and having a slice of lightly toasted sourdough piled with fresh tomatoes and herbs."

Then there are those pesky AGEs, short for Advanced Glycation End Products. These compounds are glycotoxins, and are created by cooking foods high in animal fat and protein at high temperatures. They are also found in many highly processed foods, especially those that are baked and crunchy.

"Research has found that AGEs can make cells more susceptible to damage and premature ageing, and high levels of AGEs in the diet have been linked to inflammation and the development of chronic illnesses like insulin resistance, type 2 diabetes and Alzheimer's disease.

"But it's not hard to reduce our exposure to these chemicals simply by changing how we cook," says Trickey, who runs workshops on anti-inflammatory cooking that emphasise lower-temperature cooking methods.

Her tips include:

Retire the deep fryer 

If you prefer your spuds with zero acrylamide, the best cooking method is steaming them whole with the skin on. Frying causes the most acrylamide formation; roasting and baking cause less. You can also reduce acrylamide formation in cooking by soaking raw potato slices in water for 15 to 30 minutes before roasting or frying and cooking potatoes until they're light brown, not dark brown.

…but don't be too scared of fat

If you're old enough to have cooked through the low-fat/no-fat '80s or '90s you'll know that no health conscious kitchen was complete without a spray can of oil to add just a whisper of fat to the cooking pan. It's an idea that still lingers, yet according to a 2010 report in the Journal of the American Dietetic Association, dry heat promotes formation of AGEs by 10 to 100 fold. But although foods derived from animals are prone to forming AGEs, vegetables, fruit and wholegrains contain few AGEs. Tossing vegetables in olive oil and roasting them on a gentle heat that avoids browning will reduce acrylamide and AGEs, Trickey says.  

Find healthier ways to add crunch

Our love affair with crunch keeps us coming back for crispy pan-fried, oven fried or toasted foods. But you can add texture and crunch in other ways including coating vegetables for roasting with crushed nuts or chia seeds or adding nuts and seeds to muesli. Buckinis – buckwheat groats that have been soaked then dehydrated at low temperatures to give a crunchy texture – are good in muesli too.

Use 'wet' cooking methods

Lowering the cooking temperature and using moist cooking techniques like steaming, stewing and poaching (or foil wrapping meat) will help reduce AGEs as well as other potentially harmful chemicals – heterocyclic amines (HCAs and polycyclic aromatic amines (PHAs) formed when meat, poultry or fish is pan-fried, grilled or barbecued. Stir-frying can also count as "wet" because of the extra moisture from added sauces, Trickey says. Adding a marinade with acidic ingredients like lemon juice or vinegar to meat, poultry and fish can also reduce the formation of HCAs, PHAs and AGEs.  

Be generous with vegetables, herbs and spices

Flavouring foods with antioxidant-rich herbs and spices and serving big helpings of brightly coloured vegetables will help counteract the effects of AGEs and acrylamide, Trickey says.