Abstract
Background Adoption of healthy and sustainable diets could be essential for safe-guarding the Earth’s natural resources and reducing diet-related mortality, but their adoption could be hampered if such diets proved to be more expensive and unaffordable for some populations. Therefore, we aimed to estimate the costs of healthy and sustainable diets around the world. Methods In this modelling study, we used regionally comparable food prices from the International Comparison Program for 150 countries. We paired those prices with estimates of food demand for different dietary patterns that, in modelling studies, have been associated with reductions in premature mortality and environmental resource demand, including nutritionally balanced flexitarian, pescatarian, vegetarian, and vegan diets. We used estimates of food waste and projections of food demand and prices to specify food system and socioeconomic change scenarios up to 2050. In the full cost accounting, we estimated diet-related health-care costs by pairing a comparative risk assessment of dietary risks with cost-of-illness estimates, and we estimated climate change costs by pairing the diet scenarios with greenhouse gas emission footprints and estimates of the social cost of carbon. Findings Compared with the cost of current diets, the healthy and sustainable dietary patterns were, depending on the pattern, up to 22–34% lower in cost in upper-middle-income to high-income countries on average (when considering statistical means), but at least 18–29% more expensive in lower-middle-income to low-income countries. Reductions in food waste, a favourable socioeconomic development scenario, and a fuller cost accounting that included the diet-related costs of climate change and health care in the cost of diets increased the affordability of the dietary patterns in our future projections. When these measures were combined, the healthy and sustainable dietary patterns were up to 25-29% lower in cost in low-income to lower-middle-income countries, and up to 37% lower in cost on average, for the year 2050. Variants of vegetarian and vegan dietary patterns were generally most affordable, and pescatarian diets were least affordable. Interpretation In high-income and upper-middle-income countries, dietary change interventions that incentivise adoption of healthy and sustainable diets can help consumers in those countries reduce costs while, at the same time, contribute to fulfilling national climate change commitments and reduce public health spending. In low-income and lower-middle-income countries, healthy and sustainable diets are substantially less costly than western diets and can also be cost-competitive in the medium-to-long term, subject to beneficial socioeconomic development and reductions in food waste. A fuller accounting of the costs of diets would make healthy and sustainable diets the least costly option in most countries in the future.
Generated Summary
This modelling study used regionally comparable food prices from the International Comparison Program for 150 countries to estimate the costs of different dietary patterns. The study examined dietary patterns linked to reductions in premature mortality and environmental resource demand, including nutritionally balanced flexitarian, pescatarian, vegetarian, and vegan diets. Using food waste and projections of food demand and prices up to 2050, the study estimated diet-related health-care and climate change costs. The study’s full cost accounting considered these factors, pairing diet scenarios with greenhouse gas emission footprints and estimates of the social cost of carbon. The research aimed to assess the economic dimensions, including affordability and costs of healthy and sustainable diets globally. This analysis integrated regional food prices and consumption data and a set of established healthy and sustainable dietary patterns to compare costs. The research also included waste reduction, socioeconomic changes, and full cost accounting in its analysis to provide additional insights into the relative affordability of healthy and sustainable dietary patterns in different income countries.
Key Findings & Statistics
- Compared with the cost of current diets, the healthy and sustainable dietary patterns were, depending on the pattern, up to 22–34% lower in cost in upper-middle-income to high-income countries on average.
- Healthy and sustainable diets were 18–29% more expensive in lower-middle-income to low-income countries.
- Reductions in food waste, a favourable socioeconomic development scenario, and a fuller cost accounting that included the diet-related costs of climate change and health care in the cost of diets increased the affordability of the dietary patterns in our future projections.
- The healthy and sustainable dietary patterns were up to 25-29% lower in cost in low-income to lower-middle-income countries, and up to 37% lower in cost on average, for the year 2050.
- In 2017, the average cost of diets, including food wasted by households, was $5.7 (95% CI 3.9-7.6) per person per day, ranging from $3.7 (2.2-5.2) in low-income countries to $7.5 (5.3-9.7) in upper-middle-income countries.
- In low-income and lower-middle-income countries, staple crops accounted for the greatest proportion of costs (33-35% across the two regions), followed by legumes and nuts (11-27%), meat (11% in each region), vegetables (9-14%), and fruits (9-12%).
- In high-income and upper-middle-income countries, meat accounted for the greatest proportion of costs (32-34%), followed by staples (18% in both regions), vegetables (11-24%), and fruits (8–9%).
- The alternative dietary patterns ranged from being 1-14% more expensive (high-veg pescatarian, high-grain pescatarian, flexitarian, and high-veg vegan) to 6-11% less expensive (vegetarian, high-grain vegetarian, high-grain and vegan) on average compared with current diets, with large variability across income regions.
- Food waste at the household level accounted for 29% of the costs of current diets on average, ranging from 17% in low-income countries to 35% in high-income countries.
- Halving food waste reduced the costs of current diets by 14% on average (8-17% across income regions).
- Combining dietary changes towards the different dietary patterns with reductions in food waste reduced the relative costs of those diets.
- As income increases, diets and food prices are projected to change, especially in low-income and lower-middle-income countries.
- Accounting for the food-related costs of climate change and for the diet-related health-care costs increased the average costs of current diets by 12% and 4%, respectively, and the average costs of 2050 diets by 42% and 9%, respectively.
- The combined increases were greater in high-income and upper-middle-income countries ($4.7-5.4 per day, 53-67% in 2050) than in low-income and lower-middle-income countries ($2.5-2-6 per day, 42–48% in 2050).
- The different dietary patterns were both healthier and lower in greenhouse gas emissions than current diets and the associated increases in costs were lower (on average 6-9% compared with 17% in 2017, and 18–28% compared with 51% in 2050).
- In 2017, the number of countries for which adoption of the different dietary patterns reduced the cost of diets ranged from 24 countries (16%, with a population of 2.6 billion people) for high-veg pescatarian diets to 81 countries (54%, 3.8-3.9 billion people) for high-grain vegan and vegetarian diets.
Other Important Findings
- Variants of vegetarian and vegan dietary patterns were generally most affordable, and pescatarian diets were least affordable.
- Dietary change interventions that incentivize adoption of healthy and sustainable diets can help consumers in high-income and upper-middle-income countries reduce costs while contributing to climate change commitments and public health spending.
- In low-income and lower-middle-income countries, healthy and sustainable diets are substantially less costly than western diets and can also be cost-competitive in the medium-to-long term, subject to beneficial socioeconomic development and reductions in food waste.
- A fuller accounting of the costs of diets would make healthy and sustainable diets the least costly option in most countries in the future.
- The study also found that the relative affordability was largest for vegetarian and vegan diets that focused on legumes and whole grains in place of animal products in current diets, and lowest for pescatarian diets that focused on fish and fruits and vegetables.
- In low-income countries, any diversification of their current diets would increase costs.
- Healthier and more sustainable dietary patterns are generally lower in costs than western diets.
Limitations Noted in the Document
- The cost estimates are considered conservative, as the price data was representative of supermarket prices and did not account for markups in restaurants.
- Consumption data covered basic food categories which did not allow the study to explicitly account for the consumption and prices of highly processed food products and drinks.
- Analysis of price feedbacks from dietary changes was limited to those associated with different socioeconomic trajectories.
- The valuation of the diet-related costs of climate change and health care is subject to high uncertainty.
Conclusion
The research indicates that dietary patterns, designed to improve health and environmental sustainability, can be more affordable than current diets in many high-income and middle-income countries. Conversely, these same patterns may be more expensive in low-income countries. However, the combination of waste reduction, socioeconomic changes, and a fuller cost accounting, which includes health and climate change costs, can improve the affordability across different income levels. The study’s findings support that policies that encourage the adoption of healthier, sustainable diets can reduce costs for consumers and contribute to climate change goals and public health improvements. For high-income and middle-income countries, interventions that promote healthy and sustainable diets can also help reduce costs and contribute to national climate change goals. For low-income countries, any diversification of their current diets would increase costs, and a long-term food-system perspective could help identify appropriate policy approaches, including a focus on waste reduction and development. Dietary shifts towards healthier and more sustainable eating patterns are generally less costly than current diets, and can be cost-competitive in low-income contexts if health and environmentally sensitive policy and development strategies are in place. The study emphasizes the need for comprehensive policy approaches that consider not only dietary changes but also the broader food system, waste reduction, socioeconomic conditions, and the true costs of food and diets. It suggests that any policy should consider the overall environmental impact, in addition to the health impacts, of dietary choices. The study underscores the importance of considering the interplay of various factors to increase the affordability of healthy and sustainable diets for all, including those in low-income countries.