Sustainable diet
A way of eating that seeks to reconcile health, low environmental impact, affordability and respect for cultural practices, as defined by the FAO.
A sustainable diet is not just about ecology. The FAO definition covers four dimensions at once: health, the environment, affordability and cultural acceptability. A diet that is flawless on climate grounds but too expensive, or impossible to keep up in the long run, does not meet the criteria.
The good news is that health and the environment largely converge. Eating more plants, fewer animal products, favouring seasonal produce and limiting ultra-processed foods improves both carbon footprint and nutritional quality. The two goals pull in the same direction more often than people think.
Waste weighs more than the choice of products. This is the most counter-intuitive point: throwing food away means wasting all the resources used to produce, transport and store it. Cutting your losses at home often has more effect than long deliberations over origin or production method.
Local is not an automatic guarantee either. Transport accounts for only a modest share of the footprint of most foods, far behind the way they are produced. A seasonal tomato grown in an open field 500 km away beats a local tomato grown in a heated greenhouse in winter.
Two figures give a sense of scale. The 2019 EAT-Lancet report proposed a “planetary health diet”: mostly plant-based, with small amounts of animal products, designed to feed ten billion people without exceeding environmental limits. And about a third of the food produced worldwide is wasted, which is why this lever weighs more than most shopping trade-offs.
Two final caveats. Organic farming improves soil health and biodiversity, but sometimes with lower yields, which shifts part of the problem elsewhere. And a sustainable diet must remain affordable: solutions reserved for wealthy households change nothing at the collective level. Flexitarianism and the Mediterranean diet are two concrete examples.