How supermarkets trick us into buying unhealthy food, and what we can do about it

The way food shops are laid out needs an urgent overhaul if we want to tackle the obesity crisis

Do you ever look up at those signs hanging over the aisles in supermarkets to see how you might possibly get the last three last things you need without going back to the start of the dreaded racetrack?

If you’re anything like most people, you probably begin shopping in quite an orderly fashion. With grim determination you make it through the “decompression zone” – that no-man’s land of candles and wicker baskets and lilies that retail experts have carefully designed to slow you down from street speed to shopper speed, into the “marketplace” which delivers the motherlode of freshness.

You are chicaned around the “perimeter” of the store: the edges that house the deli, bakery and butcher, and where most profit is made. Then it becomes a little more random. Halfway up one aisle, you abandon your trolley, U-turn around those “end cap” displays that are meant to entice you to impulse-buy the stuff you may not have had on your list. (What’s a breakfast bar doing beside a kettle promotion?)

With vague panic rising, you start looking up at the categories for some guidance and sanity – please, please tell me where the baking aisle is. Retail designers estimate (and they have done a lot of investigation into the micro-behaviours of customers) that after about 25 minutes in the supermarket we switch from rational to emotional decision-making. This makes us more susceptible to grabbing a packet of chocolate raisins located right next to the eggs.


Food categories – the way we see the basic groups of foods – fruits, vegetables, grains, oils, dairy and so on, are incredibly powerful. They orientate the way we tick off the shopping list, mentally accounting for the members of the family and the stages of the day. Breakfast, tick. Lunchboxes, tick. Dinners, tick. The Food Safety Authority of Ireland has done really interesting studies on the nutritional content of foods in Irish supermarkets. It found that the majority of yoghurts are not healthy choices, nor are breakfast cereals. The majority of "baby crisps" were higher in saturated fat than adult "reduced fat" crisps, while most baby biscuits were higher in sugar than plain digestive biscuits. Categories can be deceptive, even dangerous.

In the face of an obesity crisis that has caused hidden but systemic suffering and loss of life, arguably the single most powerful countermeasure we could undertake is not to ban junk food advertising to children, nor tax sugary drinks, nor place fast-food shops 100m from the school gates, but to recategorise food products so that it is easier for consumers to see how healthy they are. If that step was taken, most breakfast cereals would appear in the snack aisle, most baked goods would appear in the dessert aisle, most yoghurts would appear in the soft drinks aisle, and those rusks would appear at the confectionary check-out. It may seem trivial, but the accurate and transparent categorisation of food products is a key battle in the war on obesity.

This is because “perceptual categorisation” is a powerful phenomenon. Every object, every experience we have, is assigned to a category we have built up in our minds over time. We respond to the world by putting things into categories, not by thinking of things as individual cases. That is why we don’t run up to every person on Grafton Street we’ve never seen and greet them in astonishment of their sheer uniqueness. We scan the environment: “person”, “person”, “person”, “shop”, “person”, “litter bin”, and so on. These “heuristics” form the basis of consumer behaviour and the backbone of marketing theory.

As we work hard to build up sophisticated categories in our minds, we also outsource and entrust much of it to food firms. Do you remember the orange juice Sunny Delight? It was launched in the United Kingdom in the late 1990s, with a multi-million pound marketing campaign, and soon became one of the biggest selling drinks in the world. It was positioned as a healthy alternative to fizzy drinks. In its advertisements, Mom would stock the fridge with Sunny D so that when the kids and their friends came to visit, they'd see what a cool family they were. The central message was that the drink should be stored in the fridge. Things that are categorised as fridge-worthy are at the high-table of healthfulness.

But Sunny D wasn't technically a juice, it was a "citrus-enriched beverage" – a mere 2 per cent orange juice, added to high-fructose corn syrup and water. It could exist for years on a supermarket shelf. But the connotations of freshness that the fridge lent ensconced it firmly and unconsciously in our perceptual category of "healthy". More recently, the Irish Supreme Court ruled that the sugar content of Subway sandwich bread was so high it should be recategorised as confectionary. The court case was considering whether Subway bread should be VAT-exempt rather than concern for consumers being confused or misled in their food choices. Pringles crisps had a similar court case about a decade ago on whether its slurry of potato, wheat starch, rice flour, sunflower and maize oil dusted with monosodium glutamates, disodium inosinates, yellow colourings, and more than a dozen other ingredients constituted a "potato chip", again for tax categorisation purposes.

Most of the processed food we eat is not from mother nature but assembled in factories with laboratory agents added. The role of marketing, in a deep sense, it is to re-enchant an object. Marketing re-enchants food by shifting it to emotionally powerful images (the pastoral countryside, the jungle, the forest, the country kitchen or the bakery). It is at the level of categorisation where most of the money and effort is spent by the producers of ultra-processed food.

Take for example the case of the European Parliament recently, which rejected the meat lobby’s attempts to ban plant-based products using categories such as “burger” or “sausage” in their description of their vegetarian substitutes. Its argument was essentially that it was confusing for the customer. In reality, this illustrates how the key battles for the control of food and its consumption are not in its advertising, branding, celebrity endorsements or pricing, but in the much more subtle yet profound ways that our perceptual categories are massaged. Food brands, supermarket retailers and industry lobby groups know this.

Meanwhile, the rest of us continue to trudge down the "cereal" aisle, wondering where it is all going wrong. 

Dr Norah Campbell is associate professor of marketing at Trinity College Dublin, Sarah Browne is Assistant Professor in Marketing at TCD, and Prof Francis Finucane is a consultant endocrinologist at Galway University Hospitals and NUI Galway