We regularly hear that processed foods are not good for health. Truth or myth?

What’s wrong with food processing?

There are three major criticisms of food processing and how it affects the nutritional quality of foods. The first is that processing lowers the nutrient content of a food either by exposing it to heat or by discarding a nutrient-rich portion. Secondly, during processing so-called ‘nutrients of concern’, such as saturated fat, salt and sugar, may be added. A third criticism is that processing may alter the nature of a food unfavourably, for example, by increasing its glycaemic index.

All of these things are true, so processed foods are obviously worse for health than unprocessed foods. Right?

Not so fast.

What’s right with food processing?

If you buy a piece of lean rump steak from your local butcher, do you eat it in its natural raw form or do you toss it into a hot frying pan first? Yes, this heat processing causes some loss of nutrients but we do it because cooked meat tastes so much better than raw meat. Also, cooked meat is much safer to eat than uncooked meat.

The same issues apply when food is processed by a food manufacturer. Safety is the paramount concern and strict regulations must be adhered to. Modern processed foods are so safe that any breakdown in food safety standards usually makes front page news.

Taste versus ‘nutrients of concern’

Taste is one of key things determining whether people buy this food or that. Yet making, say, grain foods taste good inevitably involves adding some ‘nutrients of concern’. Even staple grain foods like bread have added salt, which makes the difference between a palatable product and one that very few people would buy.

Adding fewer ‘nutrients of concern’ to a food may make good sense from a nutritional point of view but if nobody buys the less palatable product the nutritional benefits are never realised.

Processed food is better than no food at all

Some natural products actually require processing to turn them into food for humans. Wheat in its raw, natural state is indigestible and passes straight through the body. But processing wheat turns it into food that feeds millions of people. The same goes for canola seeds. Canola oil certainly has fewer nutrients than the seed from which it came, but some food is better than no food. And besides, the meal from the canola seed isn’t wasted – it’s fed to animals which in turn nourish us.

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Inconsistency

Processed foods are often damned and praised selectively. Take processed milk for example: sweetening milk with sugar to make chocolate milk is generally frowned upon, yet processing milk into cheese is considered okay, despite the higher saturated fat and salt content of cheese. How come? Is it that we like the IDEA of cheese making – a process with a farmhouse tradition, and we don’t like the IDEA of making chocolate milk in a modern factory? Sounds more philosophical that scientific.

In the media we often hear that margarine is more processed than butter and therefore is a less healthy choice. Why? Isn’t the margarine richer in essential nutrients? Doesn’t margarine lower blood cholesterol relative to butter? What has processing got to do with it?

If processing fats is a concern, why aren’t we concerned about how cows process fats? Cows eat lots of essential polyunsaturated fats in grass and grain but then convert most of them to saturated and trans fats – bad fats – which end up in the milk and meat. But the adverse effects of this bovine processing seem to pass without comment.

The logic seems to be that if a cow processes fat, that’s a good thing, even if the outcome is bad. But if humans process fat, that’s a bad thing, even if the outcome is good.

Objective criteria required

Whether a food is processed or not is simply a very poor way of determining whether it’s a healthy choice. More objective criteria that are actually relevant to human health are required, such as whether a food is nutrient-rich or nutrient poor, low or high in fibre, low or high in glycaemic index, low or high in saturated and trans fats, and so on.

The trouble is, when you take this objective approach many processed foods actually appear to be healthy choices.