Nudging Meat Off the Menu: New Study Shows Protein Labelling Encourages Meat-Free Choices

Reducing meat consumption is widely recognised as a key strategy in tackling both environmental degradation and public health burdens. Yet despite growing awareness, meat remains deeply entrenched in daily diets across high-income countries.

A new study published in Frontiers in Sustainable Food Systems offers fresh insight into why, and how to change it. Authored by Chris MacDonald of the University of Cambridge, the paper explores the psychological barriers that keep consumers tethered to meat-heavy meals, and tests a simple, scalable solution: protein labelling.

The research found that when the protein content of meals was clearly displayed, consumers were more likely to choose meat-free dishes, compared to when presented with carbon labelling or no additional labelling.

The Urgency of Dietary Change

Meat consumption is a major contributor to global environmental pressures. Although this paper doesn’t provide original data on environmental impact, the connection is well established in scientific literature. For example, Crippa et al. (2021) estimate that the global food system is responsible for 34% of all anthropogenic greenhouse gas emissions, with meat and dairy among the largest contributors to those figures.

Red and processed meats have also been linked to increased risk of colorectal cancer, cardiovascular disease, and type 2 diabetes. In many countries, average consumption levels exceed both health-based guidelines and planetary boundaries.

Despite these concerns, actual reductions in meat intake remain limited. One reason, MacDonald argues, may be that most interventions rely on persuasion — not perception.

When Asking Isn’t Enough

The paper introduces the concept of the “anomaly of asking”, a persistent gap between what people say they are willing to do and what they actually choose when it comes to food. Surveys often find high levels of public willingness to reduce meat consumption, yet supermarket sales, restaurant orders, and plate waste data show minimal behavioural change.

MacDonald notes that food decisions are often made under time pressure, driven by habit, hunger, or subtle cues, not by careful reflection on values or long-term consequences. As a result, interventions focused on moral, health, or environmental reasoning may fail to shift actual behaviour.

The Protein Problem

One of the key barriers to meat reduction, the study argues, is the perception of protein inadequacy in plant-based meals. This idea is supported by prior research by Macdonald, including a 2023 survey of over 1,500 UK university students, which found that “protein” was the most cited barrier to adopting a meat-free diet.

Consumers often view meat as the most reliable or satisfying source of protein. As a result, even individuals who are open to eating less meat may avoid meat-free dishes because they assume those meals won’t be filling or nutritionally complete.

Testing the Theory

To test whether this perception could be changed, MacDonald conducted three online experiments.

Each participant was given two meal options, one meat option and one meat-free option. Participants were divided into groups that either saw no additional information, carbon information, protein information, or protein and fat information. No additional messaging was provided. There were no health claims, no sustainability logos, no guilt-tripping.

The Outcome

The results were statistically significant. Participants who saw the protein-labelled option were more likely to select meat-free meals, compared to those in the control group.

MacDonald describes this as a “nudge by proxy”, a behavioural nudge that doesn’t directly reference the target behaviour (in this case, reducing meat), but instead addresses a related belief (protein adequacy) that drives that behaviour. By alleviating concerns about protein, the intervention indirectly encouraged more sustainable choices.

Implications: Low-Cost, High-Impact

The study suggests that protein labelling could be a simple, scalable way to reduce meat consumption. Crucially, this approach does not attempt to persuade or moralise. Instead, it removes a psychological barrier that may be standing in the way of change.