Estonians’ current eating habits – particularly their fondness for meat and dairy products – put pressure on the environment and increase health risks, exceeding several of the planet’s ecological limits. Bashir Bashiri, who recently defended his doctoral thesis at the Department of Chemistry and Biotechnology of Tallinn University of Technology, explored this complex relationship using an advanced mathematical approach to answer a key question: how could people in Estonia eat in a healthier and more environmentally friendly way without abandoning their traditional food culture? His newly defended thesis offers feasible, real-world solutions.

The Scale of the Problem

According to Bashir Bashiri, analysis of Estonian dietary data revealed that the average Estonian consumes about 3,200 kilocalories per day, which is significantly more than the recommended 2,200 kilocalories. “Overconsumption is particularly striking in the case of protein intake, which is more than double the national dietary recommendation,” he noted.

Estonia’s diet is structurally unsustainable, relying heavily on animal-based foods such as red meat and dairy products, which are eaten well above recommended levels. These food groups create the largest environmental burden, leading in greenhouse gas (GHG) emissions, land use, and freshwater consumption. For example, the doctoral research showed that the current Estonian diet exceeds the planet’s tolerance limits by about 40 percent in terms of land use and by as much as 200 percent in greenhouse gas emissions.

“Animal-based foods (excluding fish) account for roughly 67% of the total land-use footprint of the average diet, driving land-cover change such as the conversion of forests into cropland. This in turn transforms carbon-sequestering areas into emission sources,” Bashiri explained. Beyond environmental harm, such diets are also linked to a higher risk of developing non-communicable diseases.

A Smart Approach to a Complex Problem

“This interconnection between environmental and health issues was the main reason we decided to study the topic,” Bashiri said. His goal was to propose a realistic and fair pathway toward a greener, healthier, and more sustainable food system for Estonia.

Traditional approaches to designing sustainable diets have often focused on a single goal, such as reducing carbon emissions, which can lead to impractical recommendations – for example, completely eliminating red meat. Bashiri instead used a Multi-Objective Optimization (MOO) method.

“In simple terms, it’s a mathematical approach that helps find the best balance when multiple objectives must be considered simultaneously,” he explained. “Imagine planning a trip – you want it to be cheap, comfortable, and fast. Achieving one of these usually means compromising on another. MOO helps identify the best possible compromise among competing priorities.”

The method allows simultaneous consideration of nutritional quality, environmental impacts (across multiple indicators), cost, and cultural compatibility – offering balanced and realistic dietary solutions.

Environmental Trade-offs

The study confirmed that sustainability cannot be measured by a single environmental indicator. “Different environmental impacts often conflict with one another – reducing one burden may inadvertently exacerbate another,” Bashiri noted.

He offered an example: land-based fish farming. Although its carbon footprint can be lower than that of red meat, it causes substantial eutrophication – nutrient pollution of water bodies. In the Estonian comparison diet, fish accounted for 23.3% of the total eutrophication impact. “So, while fish farming may be climate-friendly, it also involves significant nitrogen and phosphorus emissions,” Bashiri explained.

To address such trade-offs without overcomplicating the optimization process, he applied a multi-criteria decision-making (MCDM) method known as SURE. This approach combines five environmental footprints – land use, GHG emissions, water use, acidification, and eutrophication – into a single composite index, making it easier to manage complex compromises and apply two-dimensional optimization.
 

What a More Sustainable Estonian Diet Would Look Like

Bashiri’s results show that a sustainable Estonian diet does not require eliminating any food group entirely but rather moderate reductions and substitutions.

The key steps include:

1. Reducing dairy and red meat consumption. These two groups cause the largest environmental impacts and are currently consumed at high levels. Bashiri found that cutting dairy is the most flexible way to optimize the diet, while limiting red meat yields benefits across nearly all environmental indicators.
2. Increasing foods with lower impacts. The models consistently recommend a greater share of tubers (e.g., potatoes) and cereals, which meet nutritional needs with smaller environmental footprints.
3. Cutting down on sugar. This appeared in all optimal diet scenarios – limiting sugary and processed foods benefits both health and the environment.
4. Consuming fish in moderation. Given its significant eutrophication impact, fish should be eaten cautiously.
5. Cultural acceptability is also crucial. The optimization aimed to minimize deviation from the current average diet, emphasizing gradual and achievable change. “The study highlights a step-by-step approach – small but realistic shifts can lead to substantial long-term benefits,” Bashiri said. Even moderate improvements, such as a 15% reduction in land-use footprint, could be achieved without radically changing eating habits.
    

Barriers and Solutions

While an optimal diet can be designed mathematically, implementing it faces practical barriers. Literature review revealed the main obstacles: low food literacy, price and availability of sustainable foods, convenience, and lack of skills or motivation to manage one’s diet.

Overcoming these requires a comprehensive, multi-level strategy. According to Bashiri, the most effective approach in Estonia would combine public catering reform with improved food education.

“Public catering means strengthening sustainability criteria in schools, hospitals, and other institutions,” he explained. “These institutions can use their purchasing power to increase the availability of sustainable foods and make them the default choice, helping to shape new habits.”

Raising food literacy includes developing knowledge and cooking skills, for instance through plant-based cooking programs in schools. “This helps people feel more confident and dispels misconceptions that sustainable eating is expensive, bland, or difficult,” Bashiri added.

Additional measures could include better food labelling and financial incentives – such as subsidies for sustainable products or taxes on unhealthy foods.

Estonia’s Path Forward

Bashiri’s findings align closely with the recently published EAT-Lancet 2.0 raporti soovitustega, mis kutsub üles globaalsele "planeedi tervise dieedile". Mõlemad rõhutavad liikumist taimsema ja toiteväärtuslikuma toitumise suunas, vähendades liha- ja piimatoodete tarbimist. Erinevus seisneb peamiselt meetodis. Bashiri kasutas mitme eesmärgi optimeerimist, mis võimaldab paremini arvestada kohalikke eripärasid ja kultuurilist sobivust. "Meie välja töötatud stsenaariume võib käsitleda kui Eesti-põhist "planeedi tervise dieedi" versiooni – sellist, mis on kohandatud kohalikele toidueelistustele ja tarbimismustritele," ütles Bashiri.

which calls for a global “Planetary Health Diet.” Both emphasize shifting toward more plant-based and nutrient-rich eating patterns while reducing meat and dairy consumption. The difference lies in the method: Bashiri’s multi-objective optimization approach allows tailoring recommendations to local contexts and cultural preferences.

“Our proposed scenarios can be seen as an Estonia-specific version of the Planetary Health Diet – adapted to local food traditions and consumption patterns,” Bashiri said.

His main message to policymakers and the public is that change is both possible and necessary. “Transforming a society’s eating habits won’t happen overnight, but we can start with small steps today,” he emphasized. Even moderate, gradual changes in the right direction can, over time, bring significant and lasting benefits for both human health and the environment.

Bashiri’s research provides a scientifically grounded framework and tools for updating Estonia’s official dietary guidelines so that they better reflect health, environmental, and cultural dimensions.

Bashir Bashiri defended his doctoral thesis, “A multi-objective optimization approach for design and implementation of sustainable diets,” on October 23 at Tallinn University of Technology. The thesis was supervised by Emeritus Professor Raivo Vilu (TalTech) and Researcher Olga Gavrilova (AS TFTAK), with opponents Dr. Mika Jalava (Aalto University) and Senior Researcher Ellen Trolle (Technical University of Denmark).

The thesis is available in TalTech´s digital repository.