Major impact calls for major interventions

Imagine visiting a supermarket tomorrow that looks completely different. Healthy and sustainable products have been allocated more shelf space, with a greater variety and more special offers. Green arrows on the floor guide you past healthy products; for less healthy and sustainable choices, you have to make a detour to the far corners of the shop.

This ‘ideal supermarket’ is not a blueprint, but a thought experiment. What does a shop look like that helps people stick to their resolutions? “People think they choose what they want to eat, but the food environment exerts an incredibly strong influence,” says Marleen Onwezen, a behavioural scientist at Wageningen Social & Economic Research. “The ideal supermarket helps you convert your intentions into action, rather than pushing you in the opposite direction.”

Through its annual Protein Monitor, Wageningen University & Research tracks the ratio of animal to plant-based proteins in Dutch supermarkets. In 2024, 38% of high-protein products were plant-based, but consumption lagged behind. At the same time, the national target is for half of the protein consumed to come from plant-based sources by 2030.

Simply stocking more plant-based products is not enough. Yet many behavioural interventions focus on just one small change: a campaign, a quality label, a promotional offer or a meat substitute served next to the meat. Such measures can have an effect, but this is often limited or temporary.

Researchers, government agencies and businesses often opt for one-off nudges or short-term interventions. These can be examined safely and systematically. A restaurant is more likely to change its menu than to overhaul its entire operational management; a supermarket is more likely to introduce a single product than to reorganise entire product groups.

This creates a gap between the major change that is needed and the cautious interventions currently being explored. Onwezen and her colleague Hans Dagevos refer to this as the ‘aspiration-action gap’: we set ambitious goals, but tend to trial small steps that leave the existing system largely intact. That is why they are calling for a Bolder & Broader behavioural science.

Bolder means that researchers, policy makers and businesses first determine where they ultimately want to go and then work backwards from there: what is needed to achieve that vision of the future? They are therefore not only basing their approach on what appears feasible within the current system, but also on what is required to achieve sustainability and health targets. What changes are necessary in terms of product range, pricing, promotion and legislation, and what skills do consumers need? Check out that ideal supermarket again. Plant-based products are no longer the exception there. The meat aisle is smaller, whilst pulses and plant-based alternatives are given more space, variety and promotion. “If you want to make a big impact, you have to be willing to take bold action,” says Onwezen.

According to Onwezen, animal proteins now get more shelf space and marketing attention. Without saying anything, the supermarket is conveying the message: ‘Most people are buying this, so this is normal.’ Supermarkets, restaurants and canteens can change the food environment, but are cautious about making major changes. This creates a vicious circle: businesses believe that customers mainly want animal-based products, so they supply them in abundance, thus reinforcing the existing norm.

The vision of the future doesn’t have to be as spectacular as possible. The protein transition is about striking a different balance between animal and plant-based proteins, not necessarily about a supermarket without meat. A long-term vision must be ambitious enough to provide direction, but not so far removed from reality that nobody knows where to start.

Nor does any one party determine what the ideal looks like. Supermarkets wield a great deal of power, but producers, government agencies, social organisations and consumers also exert influence. The ideal supermarket therefore prompts us to ask: what sort of food environment do we want and what is needed to achieve it?

An ambitious vision does not automatically translate into different buying behaviour. This often requires several factors to change at the same time. Broader means that researchers do not therefore examine a single barrier or intervention in isolation, but view behaviour in the context of the environment in which it arises. Besides motivation and skills, this approach also takes into account social, economic, political and environmental factors that enable or restrict choices.

This calls for a combination of measures at various levels. A strategy or campaign can help, but the environment must also make the desired behaviour possible and appealing. Consider a different shelf layout, lower prices for plant-based products, procurement rules for canteens and legislation governing the range of products on offer. Measures such as these change the circumstances in which people make their choices.

Many models identify three conditions for behavioural change: people must be motivated, be able to carry out the behaviour and their environment must support this. Researchers often look for the main barrier. If motivation is the problem, a campaign is launched; if knowledge is lacking, guidance is provided; if a product is unavailable, the range is adjusted. 
“That approach assumes there is a single bottleneck,” says Onwezen. “But lasting change often requires several conditions to be met at the same time.”

In an ideal supermarket, for example, plant-based products would be more visible and more affordable. At the same time, customers are given cooking tips and special offers establish a new social norm. In this way, interventions at the individual and system levels reinforce each other.

But a supportive environment alone is not enough: people must also be able to incorporate new choices into their daily routines. According to Onwezen, skills are just as important as motivation. “Many people cook a limited number of standard dishes. Anyone who wants to eat less meat but isn’t sure how to incorporate lentils or beans into their regular meals will easily fall back on the familiar pattern.” Someone who usually cooks meat and two veg won’t change their routine just because they were given a recipe for bean burgers.

The Broader approach therefore goes beyond simply offering a recipe. The product must be affordable and readily available, and the dish must suit a person’s taste, schedule and routine. If pasta with lentils eventually becomes a regular feature in the repertoire, the effect will be significant.

“Habits are hard to change,” says Onwezen, “precisely because they save us from having to think about every choice in detail.” Routines can change, for example following a move or the birth of a child. And timing matters in the shop too. At the start of a shopping trip, people may be more focused on making conscious choices than at the end, when tiredness and temptation take their toll.

This approach should also ensure that the responsibility does not fall entirely on the consumer. Onwezen: “Many interventions ask people to make better choices in an environment that encourages the opposite. Anyone with enough time, money and mental capacity can compare labels and try out new recipes. For people who already have a lot on their minds, that’s not so obvious.”

That could increase inequality. According to Onwezen, it is not just a question of price. Sustainable food doesn’t always have to be more expensive; lentils are usually cheaper than meat. Time, knowledge and familiarity also determine what is feasible. A broad, system-wide approach must ensure that eating more sustainably and healthily does not primarily become easier for highly educated and affluent consumers. The environment should support everyone in making their preferred choice.

The Bolder and Broader approach does, however, make the research more complicated. Anyone implementing several interventions at the same time can measure the overall impact, but it is less straightforward to determine which component caused which effect. And it is precisely that combination that is relevant, says Onwezen. “Science already knows a great deal about individual mechanisms, and that is certainly valuable. The next question is what happens when that knowledge is pooled and applied on a larger scale.”

That requires collaboration across disciplines. Behaviour is shaped not only by psychology, but also by economics, policy, institutions, culture and food chains. In the project Long-term behaviour change, researchers are also building a database that studies behaviour over a longer period. Data covering a period of two to three years will provide a clearer picture of whether a change is here to stay, whether it will disappear, or whether it will give way to other habits.

Artificial intelligence can also help. AI can analyse video footage and provide insights into what happens to purchased products in the home. In addition, the researchers are working on a local AI application which, acting as a personal diet coach, can suggest a more sustainable version of a familiar dish, tailored to the user’s taste, cooking experience and values such as health, animal welfare or convenience.

The Knowledge Base project aims to help researchers, policy makers and businesses better understand how behavioural change can be sustained. The challenge lies not only in how individual interventions work, but above all in how different interventions can reinforce each other and how behavioural change can be scaled up and sustained. Insights from behavioural science must be linked to practical tools, ranging from procurement rules and labelling to pricing policy and legislation.

“We understand just how complicated it is,” says Onwezen. “But by thinking and acting more boldly and broadly, behavioural interventions can have a much greater impact. We’re holding ourselves back by continuing to operate only on a small scale.”

The protein transition is a key case study within the project, but the principles are applicable more widely. Whether the issue is climate adaptation, biodiversity, agriculture or fishery, different values and interests come into play, but the same question remains: how do you change behaviour within a system that constantly reinforces existing behaviour?

The ideal supermarket does not provide a definitive answer to that question. However, it does force researchers, businesses and policy makers to look beyond the next quality label, price tag or green tick. Sometimes change doesn’t start with the next small step, but with the courage to first decide where you really want to go.