Ultra-processed food – time for a new food scare?

[this post draws extensively on a journal paper by Monteiro et al, 2018, so if you prefer journal papers to blog posts, read that instead].

The media is constantly bombarding us with dietary advice, whether it’s related to so-called ‘super foods’, foods that cause cancer, whether 5 a day fruit and veg is really enough, whether a glass of wine a day is good or bad, and then a whole load of nonsense on how to lose weight. The number of vegetarians and vegans is on the rise, and with it comes an ever-increasing choice of meat or cheese substitutes. I’m a low meat eater (1-2 times/week), and whilst I eat quorn and tofu, I’m not very familiar with many other meat/cheese substitutes. This week I was given a packet of ‘original flavour slices’. The packaging is nice, they’ve got a Vegan Society logo on them and they look like they might contain something resembling cheese but healthier.

When I opened the packet they looked and tasted like processed cheese (I liked the taste, not dissimilar to Edam). The packet says ‘free from’ a whole load of things, including gluten, lactose, nuts and dairy. Which begs the question, what’s actually in it, and what is it substituting for? Reading the small print on the back was pretty shocking. This product contains virtually nothing of nutritional value at all; zero protein, mostly fat (from coconut oil), some starch, and a lot of water and some flavourings. It’s something to put between two slices of bread and call a sandwich, but that’s about it. If you’re a vegan with a cheese craving they’d be great, but the complete absence of protein means it’s definitely not a cheese substitute in nutritional terms.

For a few years now, I’ve had a vague rule (vague as in I break it more often than I’d care to admit!) to not buy food with more than about 5 things on the list of ingredients, which I named ‘the rule of 5’. This came from a notion that processed food is probably a ‘bad thing’. In the last year or so, there’s been an unexpected benefit to this; I’m now of an age where I am on the cusp of needing glasses to read small print on labels, and the great thing about the rule of 5 is that I don’t need to read the list of ingredients to see what they actually are, I can just vaguely squint at the list to see how long it is. I had no particular evidence to back up the rule of 5, and will happily admit it has been more a worldview than anything else. However, recently I’ve been reading about ultra-processed food and the NOVA food classification system.

The NOVA system subdivides foods into 4 groups, based on the nature, extent and purpose of food processing. Clearly, there are some food processing techniques that are beneficial to human health and food preservation; chilling, vacuum packing, pasteurising and drying being obvious examples, hence the importance of including the purpose of processing within the classification scheme. The system will certainly be criticised by food manufacturers, particularly given that there could be an element of subjectivity in classifying. But many of us are uneasy about the marketing of processed food, the scale of which is vast compared to the marketing of raw food products, and the effect this has on people’s buying habits is cause for concern.

Is food processing something to worry about? Conventional classification systems tend to group foods according to biological origin, so a fresh chicken would be in the same category as chicken nuggets, and oats would be in the same category as Kelloggs crunchy nut cornflakes. Consequently, a system based on biological origin doesn’t necessarily reflect whether or not a product is good for you. Food processing techniques can drastically affect the healthiness or otherwise of a meal by enabling us to eat things that aren’t really food; additives are now extensively used to improve the flavour, attractiveness and general palatability of oils and refined sugars, and so we are now eating large quantities of manufactured substances that never really resembled food in the first place. The proportion of our energy intake that comes from ultra-processed foods is increasing rapidly, so understanding the impact this will have on our health is important.

The NOVA classification scheme is outlined below, the source article and description is here.


Are group 4 foods actually bad for us?

A key difficulty with the classification scheme is that it may prove virtually impossible to study the health impacts of group 4 foods in populations. To conduct an ideal experiment one would need two groups of people with the only variation between the two groups being their diet, and you would then follow health outcomes over several decades. This is never going to happen; in a recent study of cancer risk, people eating group 4 foods were more likely to smoke, took less exercise, had lower levels of education and consumed excess calories. We know the risks that are associated with these things, so the authors took these risks into account when doing statistical analysis of cancer rates (e.g. by subtracting the impact of smoking on cancer from the results from that group in the study). This study did show a slight increase in some types of cancer even when other differences between the study groups were accounted for, but there were a number of other difficulties with the study (e.g. the participants were self-selecting, they were mostly women and their food intake was self-reported via an online questionnaire).

There is an enormous weight of medical evidence indicating that excess salt, sugar and fat are bad for us. We also know that group 4 foods often have high levels of these things and low levels of nutrients that we may lack. Even the group 4 foods that are fortified with substances that are good for us (e.g. breakfast cereals often have minerals and vitamins added to them) often have high levels of what are known as ‘empty calories’ (the original flavour slices are an excellent example; per 100g they contain 23g fat, 2.3g salt and 0g of protein, but the manufacturers have added vitamin B12). Viewed in this way we could say that the lack of evidence relating to group 4 foods per se is not necessarily a problem, and that the classification system is simply a way of communicating or simplifying nutritional information.

How might this relate to other nutritional information and easy ways for consumers to make healthy choices? The UK, alongside other EU countries has mandatory nutritional labelling on processed food products on the back of the packet, and the UK also has a widely used front of pack labelling system that includes a traffic light colour scheme. There is a lot of evidence to suggest that these labels help consumers identify healthy versus unhealthy foods (reviewed here), but since the front of pack label is not compulsory, it’s easy to mistakenly buy stuff that isn’t very healthy. The original flavour slices package wouldn’t look nearly so attractive if it was labelled in this way (they would be red for fat, red for saturated fat, amber for sugars and red for salt!).

traffic light
Front of pack nutritional labelling as used in the UK (on a voluntary basis).

Final thoughts

I like the NOVA classification because it seems to allow the complexity of nutrition to be simplified into robust dietary advice, and it’s something that we could all understand enough to put into practice. The simplest conclusion to draw from reading about the NOVA classification is that we should cook most food ourselves. If we did this, most of our diet would be made up of food that we prepare ourselves from raw ingredients, which in NOVA-speak would roughly equate to eating a lot of group 1 foods, and combining some group 1 and 2 foods to produce meals which might be group 3. This doesn’t mean we have to be one of those smug wholesome people who cook every day; in my case I have a freezer and a load of plastic tubs, so I only need to be smug and wholesome a couple of times a week. In general terms, the classification scheme provides some scientific rationale to the ‘rule of 5’ I had set myself, and I’m going to ponder over the next few months the extent to which this simplification is valid/useful (e.g. for products without a front of pack traffic light label).

It might conceivably be possible to eat mostly group 4 foods and be healthy (many group 4 foods are fortified with nutrients partly as a marketing ploy), but it would be difficult not to eat excess salt, sugar and fat. That’s not to say we should never eat these foods; we eat food for all sorts of reasons other than its nutritional value. Our eating habits are intrinsically linked with pleasure and hedonism, food can be joyful, comforting and loving. And the pretend cheese was really pretty nice.

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