AbstractFood systems have significant externalities that are not reflected in market prices. A first step to correct parts of these externalities is to make them transparent through “true‐” or full‐cost accounting. Estimates of the external health and environmental costs of food systems at a global level suggest that they may be about two times larger than food valued at market prices, that is, about 20 trillion US$ of externalities versus 9 trillion US$ of food value in the markets. The agricultural economics profession is challenged to move the true cost research agenda forward by identifying realistic pathways for internalizing some of the large food system externalities. Moving from true cost accounting (TCA) to policy action needs to involve citizens and policy‐making bodies because internalizing externalities requires buy‐in. This relates for instance, to policy instruments such as product labeling, nudging, and differential taxes and subsidies to incentivize healthy diets and disincentivize food waste. Agricultural economics will need to accompany the implementation of any true cost approaches with scrutiny in terms of the efficiency, welfare, ecological, and distributional effects of such policies.