Beyond calories: Benchmarking access to healthy diets for people, planet, and policy

The suite of indicators measuring the Cost and Affordability of a Healthy Diet, known as “CoAHD”, was launched in 2020 and is now an established set of metrics for tracking food and nutrition security worldwide. The indicators are jointly produced and published semiannually by FAO and the World Bank and featured in The State of Food Security and Nutrition in the World (SOFI). According to the latest estimates, nearly 2.8 billion people globally are unable to afford a healthy diet, which cost roughly $3.96 per person per day in 2022, expressed in current purchasing power parity (PPP) dollars.
 

Constructing the Healthy Diet Basket: a data-driven approach

At the core of the CoAHD is the Healthy Diet Basket, a global standard derived from representative national food-based dietary guidelines that constitute countries’ own official definitions of a nutritionally-adequate and culturally-relevant diet. The Healthy Diet Basket reflects the commonalities of national guidelines across countries in terms of the proportions needed of six food groups. While the structure is consistent across countries, the specific foods vary by country based on locally available items. At a given time and place of measurement, the least expensive items in each food group are identified from the retail price data.

Compared to more complex diet models, the Healthy Diet Basket offers a transparent and simple set of criteria for diets that are nutritionally adequate and balanced. And because it is derived from national guidelines, the Healthy Diet Basket allows for both nutritional relevance and alignment with government policies, while remaining comparable across countries for global monitoring.

The global estimates of cost are based on price data from the International Comparison Program, a statistical program overseen by the United Nations Statistical Commission and managed by the World Bank’s Development Data Group, covering nearly 200 countries across the globe.
 

Three Key Insights from the Healthy Diet Basket

Our recent analysis, published in Nature Food, compares the Healthy Diet Basket to 16 national dietary guidelines, as well as the EAT-Lancet reference diet, introduced in 2019 as a healthy dietary pattern designed for environmental sustainability. A total of over 3,000 daily diet baskets in up to 172 countries were thus calculated for the analysis using food price data from the 2021 International Comparison Program. The results provide key insights across three dimensions: cost, nutrition, and environmental sustainability.

Monetary cost
In 2021, the cost of diets meeting the Healthy Diet Basket standards using the least expensive locally available foods had a global mean of $3.68 per person per day, slightly lower than the global average cost of national guidelines ($4.16) and the EAT-Lancet diet ($4.48).

The Healthy Diet Basket targets can be met at slightly lower cost than national guideline targets because the basket represents commonalities across national guidelines, omitting country-specific requirements that generally raise costs, such as requiring high amounts of dairy or nuts and seeds for example. The Healthy Diet Basket identifies the implicit consensus across countries on the make-up of a healthy diet, and the observation that the Healthy Diet Basket does not overestimate cost compared to national guidelines is important for its use as a global standard for cost and affordability.

Nutritional quality
Even when selecting the least expensive foods in the market, we find that consuming the food groups in the amounts recommended by dietary guidelines meet nearly all nutritional requirements. The same result is true for the Healthy Diet Basket. This further validates its use as a global standard which adequately represents the universe of national food-based dietary guidelines.

The least expensive items meeting the Healthy Diet Basket also consistently meet most World Health Organization (WHO) healthy diet recommendations for the prevention of noncommunicable diseases (8.7 out of 10 recommendations on average), such as limits on sugar, salt, and red and processed meat. These results verify that national guidelines are doing what they are designed to do: define diets that provide adequate nutrients and minimize risk of diet-related noncommunicable diseases, even under low-cost scenarios.
 

Environmental sustainability
The environmental footprints of Healthy Diet Basket-based diets were comparable to those of the EAT-Lancet reference diet. Least expensive diets meeting the Healthy Diet Basket produced an average of 1.85 kg CO₂-equivalent greenhouse gas emissions per person per day, versus 1.45 kg for EAT-Lancet and 1.82 kg for national guidelines. These are all about half of the average global carbon footprint of current diets (3.24 kg).

Water use was also almost identical for least expensive diets meeting the Healthy Diet Basket, national guidelines, and the EAT-Lancet diet. These findings highlight that the Healthy Diet Basket is both healthy and sustainable.  

These results are primarily driven by the current consumption of animal-source foods above dietary recommendations, particularly in higher-income countries, and the fact that low-cost items tend to be less resource-intensive.

Click through the visualization below to compare the diets by income group for each dimension.

With so many people unable to afford Healthy Diet Basket-based meals, particularly in low- and middle-income countries, the suite of CoAHD indicators based on the Healthy Diet Basket methodology provides critical insights into where policies can be targeted to improve food and nutrition security across the world.

Source : World Bank