What Really Motivates People to Eat Sustainably

Dietary counseling should go beyond health-centric advice to also engage environmental and ethical dimensions — not as an afterthought, but as motivators that can anchor long-term behavior change.

Most of us know we should eat better - for our health, and for the planet. Unhealthy diets are among the leading causes of chronic disease and early death worldwide, and the way we currently produce and consume food is one of the main drivers of climate change, biodiversity loss, and environmental degradation. Yet knowing all this is rarely enough to change how we eat. What moves people to change, and to keep changing? That is the question at the heart of our recently published paper.

Over a full year following 12 adults in Barcelona, we found that health was what first moved most people to change their diet, but it was not the only motive that kept them going: concerns for the environment and ethics grew significantly over time. People became more aware of where their food came from, how it was produced, and what it meant for the planet and for the people in the supply chain. Over time for some people, these concerns had become as important as health in guiding their choices. Price became less of a barrier: participants found that eating more sustainably could be more affordable than they had assumed, especially when buying seasonal produce, planning meals better, and wasting less food.

Health was what first moved most people to change their diet, but it was not the only motive that kept them going: concerns for the environment and ethics grew significantly over time.

Eating better for our health, for the planet, for others

But what does "eating sustainably" actually mean? In this study, we used a broad definition that goes beyond simply eating more plants or reducing red meat. A sustainable diet is healthy and predominantly plant-based - rich in vegetables, fruits, whole grains, and legumes, and low in red and processed meat and ultra-processed foods. But it is also about how you eat: reducing food waste, choosing seasonal and minimally packaged foods, and supporting fairly sourced products that ensure fair wages and local economies. A way of eating that is good for your health, people and planet at the same time.

What does "eating sustainably" actually mean? A way of eating that is good for your health, people and planet at the same time.

The intervention consisted of twice-weekly app-based messages and three personalized online feedback sessions tailored to what participants had been eating in the weeks before. All 12 completed the full year. Most reduced red and processed meat and ultra-processed foods, and increased vegetables, fruits, and legumes. Many went further, reducing food waste, buying local, choosing seasonal. Changes beyond the plate.

Impact beyond the plate

We also heard powerful personal stories. One participant told us they had always thought sustainable food was exclusively about the environment, never considering the people who grow and produce it. Another described a shift that went well beyond what they ate: a deeper relationship with nature, a more holistic way of seeing their everyday choices. Several mentioned that simply answering the weekly questionnaire helped them notice patterns they had never been aware of before. Self-monitoring wasn't just measurement, it became part of the change itself.

Simply answering the weekly questionnaire helped them notice patterns they had never been aware of before. Self-monitoring wasn't just measurement, it became part of the change itself."

The desire to eat better can grow stronger

Something else caught our attention: the role of habits. As participants settled into new routines - choosing local vegetables, skipping processed meats, cooking more with legumes - their new practices became more automatic. And this sense of routine grew alongside their environmental awareness and confidence in their own choices.

What does this mean in practice? Our findings suggest that dietary counseling should go beyond health-centric advice to also engage environmental and ethical dimensions — not as an afterthought, but as motivators that can anchor long-term behavior change. Digital tools that can adapt to each person's evolving motivational profile hold particular promise. That said, cost, time, and social pressures remained real barriers for some participants. Sustainable diets need to be accessible to everyone — not just those already motivated and resourced to choose them. Individual-level support must be accompanied by structural changes at the policy level.

Our findings suggest that dietary counseling should go beyond health-centric advice to also engage environmental and ethical dimensions — not as an afterthought, but as motivators that can anchor long-term behavior change.

This study is part of a larger project that also developed and validated REFRESH, a brief dietary screener for the Spanish and Mediterranean context, and produced a separate pilot study on the feasibility and impact of the full intervention. Together, they offer a fuller picture of what it takes to move people toward more sustainable eating. The desire to eat better - for our health, for the planet, for others - already exists in most people. What this work suggests is that, given the right conditions, it can grow stronger.

[Laura Bervian is a Medical Doctor from Brazil based in Barcelona. She is a consultant at the Education Department of ISGlobal and has an online practice focused on Lifestyle Medicine and Phytotherapy, supporting people in building healthier and more sustainable habits in their daily lives. You can connect through website, LinkedIn , ORCID and Instagram.]