Are processed foods ever better than fresh foods?
In terms of which has the most health benefit - fresh or processed foods, the answer seems obvious, doesn’t it?
But in fact, "To say all processed food is bad is a mistake," said Dariush Mozaffarian, the dean of Tufts University's Friedman School of Nutrition Science and Policy.
"I think it's interesting, even the question ‘fresh versus processed’ ... as though they were opposites.
"You can have something that's fresh and processed and something that's fresh and not processed."
Feeling confused yet? Well, the Americans have a different way of classifying what is legally “fresh” and what isn’t. A legally fresh food can still have approved waxes or coatings (such as on apples or lemons); it can have pesticides added after it is picked; or can be mildly washed in chlorine or acid (think salad leaves) or treated with a capped level of ionising radiation.
Everything else is considered processed, such as homemade bread or greens that you steam before serving.
"Cooking is processing at the end of the day, so to call all processed foods bad is just silly," says dietitian Dr Joanna McMillan.
When it’s looked at within these terms, then processed foods can indeed be better for us.
"Some processing makes nutrients or phytochemicals more available to us – lycopene in tomatoes is a classic example," says Dr McMillan. "You get far more lycopene from tomato paste than raw tomatoes."
Another often cited example is the freezing of foods, which renders them “processed” foods.
"Freezing is an excellent way of preserving food without the need to add chemical preservatives," explains Dr McMillan.
"Freezing also preserves the nutrients. Veggies and fruit are frozen on the day they are picked. Compare that the produce that is picked, transported to the supermarket, sat on shelf and then sat in our kitchen for however long before eating."
Looking at the vitamin content, she notes "Vitamin C declines rapidly after picking and so levels tend to be much higher in frozen produce. It's not the only nutrient this applies to. It's only the texture that is affected by the freezing and thawing process – nutritionally these foods are just as good for us."
But that doesn’t mean you should run out and buy frozen pizzas and bottles of soft drink and think that you are eating well. There is a big difference in the types of processed foods.
"I've been purposefully using the term highly processed in an albeit clumsy attempt at differentiating what we mean," says Dr McMillan.
We are eating "huge amounts" of highly processed foods.
In an average day, an Aussie eats around three kilograms of food and drink. Over one third of this weight is coming from highly processed foods such as cake, soft drink, biscuits and alcohol. It is these processed foods that can really affect our health (and our waist line). In this respect, the argument of whether a frozen item is better than a canned item is really irrelevant. For instance a product that comes in a can is often higher in salt, but much of this can be rinsed away, says Dr McMillan.
"Canned legumes are much more likely to be eaten than those bought dried (soaking overnight and then boiling for hours just won't happen in most homes!)," she notes.
"In fact with the right canned produce and packet dried produce in your pantry, along with some frozen vegies you can produce several pretty healthy meals without any 'fresh' ingredients."
It’s important to keep our perspective in this area.
"I'm a cardiologist," said Mozaffarian, "and I had a patient come in once asking about salmon. He said, 'I heard there's PCBs in salmon. Should I be eating wild salmon or farmed salmon?' I said, 'Stop smoking.'"
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