Country-Specific Sustainable Diets Using Optimization Algorithm

Current
diets of most nations either do not meet the nutrition
recommendations or transgress environmental planetary boundaries or
both. Transitioning toward sustainable diets that are nutritionally
adequate and low in environmental impact is key in achieving the United
Nations’ Sustainable Development Goals. However, designing
region-specific sustainable diets that are culturally acceptable is
a formidable challenge. Recent studies have suggested that optimization
algorithms offer a potential solution to the above challenge, but
the evidence is mostly based on case studies from high-income nations
using widely varying constraints and algorithms. Here, we employ nonlinear
optimization modeling with a consistent study design to identify diets
for 152 countries that meet four cultural acceptability constraints,
five food-related per capita environmental planetary boundaries (carbon
emissions, water, land, nitrogen, and phosphorus use), and the daily
recommended levels for 29 nutrients. The results show that a considerable
departure from current dietary behavior is required for all countries.
The required changes in intake amounts of 221 food items are highly
country-specific but in general point toward a need to reduce the
intake of meat, dairy, rice, and sugar and an increase in fruits,
vegetables, pulses, nuts, and other grains. The constraints for fiber,
vitamin B12, vitamin E, and saturated fats and the planetary boundaries
for carbon emissions and nitrogen application were the most difficult
to meet, suggesting the need to pay special attention to them. The
analysis demonstrates that nonlinear optimization is a powerful tool
to design diets achieving multiple objectives.