What will we eat in twenty years? Science searches for the diet shift that keeps people and the planet healthy
The way people eat is simultaneously one of the biggest drivers of chronic disease and one of the biggest drivers of climate change. An analysis in Science lays out which strategies could genuinely help drive the transition to a diet that is both sustainable and healthy, and which obstacles still stand in the way.
The core of the problem is well established: Western dietary patterns, defined by heavy consumption of meat, processed foods and sugar, contribute to cardiovascular disease, type 2 diabetes, certain cancers and premature death. At the same time, livestock farming accounts for a large share of global greenhouse gas emissions, deforestation and water pollution. The fix sounds straightforward, eat more plants, eat less ultra-processed food, but for billions of people that shift is practically out of reach, blocked by cultural, economic and political barriers.
The authors, publishing in Science, examine those barriers alongside the levers that could move them. They make the case for systemic change: altering individual behaviour is not enough as long as the food environment, availability, pricing and marketing all continue to make unhealthy choices the default. Interventions that rely solely on raising awareness have a patchy track record. What appears to work better is changing what is on offer, what it costs and what is considered normal, ideally all at once.
Equity: the blind spot in the debate
One of the most striking elements of the analysis is its emphasis on fairness. Dietary recommendations that are technically sound but practically unaffordable or culturally alien to large parts of the world's population are unlikely to move the needle. The shift toward more sustainable eating patterns risks becoming a privilege reserved for high-income people in wealthy countries, while the burdens of climate change and food insecurity fall hardest on the most vulnerable communities.
That makes dietary transition a political question, not just a scientific or behavioural one. The authors call for policies that make healthy, sustainable choices cheaper and more accessible, while accounting for the enormous diversity of food cultures around the world. A diet considered ideal in the Netherlands will not work, without significant adaptation, in Nigeria or India.
Longevity and diet: an equation with missing pieces
From a longevity perspective, diet is one of the most robustly supported lifestyle factors for healthy aging. Mediterranean and plant-focused eating patterns are consistently linked to lower mortality and fewer age-related diseases. But the question of how to translate that knowledge into large-scale behaviour change, on a scale that also serves climate targets, remains unanswered. Science knows what works; making it work for everyone is an entirely different challenge.