Mari Wollmar

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Opportunities and challenges with the shift to climate-adapted food consumption

This thesis explores the transition toward climate-adapted food consumption, combining insights from both public and private domains. Through four studies, the thesis investigates the balance between reducing carbon footprint (CO2e) and ensuring nutritional adequacy, revealing overlooked tensions in our shift toward sustainable diets. Rather than presenting findings by individual studies, this thesis organizes results around three interrelated themes that emerged across all four papers. The first theme examines school meals as potential climate champions, revealing both opportunities and challenges in public meal settings. The second theme explores how gender shapes nutritional needs and dietary behaviors in climate-adapted food practices. The third theme investigates the relationship between physical activity levels and CO2e, identifying pathways to unite active lifestyles with sustainability. In school meal menus across Sweden, climate adaptation is taking center stage. Yet beneath these well-intentioned changes lies an unexpected nutritional dilemma. The analysis of municipal school meal programs revealed a troubling relationship, as CO2e emissions decreased, iron bioavailability declined as well. This finding raises important questions about the nutritional adequacy of climate adapted menus, especially for adolescent girls. The paradox became particularly evident in soy-based meals. These meals contained the highest total iron, simultaneously they had the lowest amount of absorbable iron, with minimal bioavailability. None of the analyzed menus provided enough absorbable iron for female pupils with higher needs, highlighting how climate-adapted meal planning may inadvertently create nutritional blind spots. To address this challenge, hybrid recipe formulations that bridged the divide between climate goals and nutritional needs was developed. By combining plant ingredients with modest amount of meat together with vitamin C rich foods, these recipes achieved significant CO2e reductions while maintaining adequate absorbable iron levels. Consumer evaluations revealed that these hybrid approaches maintained high acceptance levels, suggesting that balancing nutrition, taste, and sustainability is entirely possible. Throughout this thesis, gender emerged as a powerful lens for understanding sustainable food transitions. A consistent pattern appeared: women demonstrated stronger climate consciousness in their food consumption but faced greater nutritional vulnerabilities when adopting low-carbon diets. Female participants consistently consumed less energy than recommended, creating a nutritional deficit that impacts micronutrient intake. This was especially pronounced among physically active women, who averaged well below their estimated requirements. This is concerning given their elevated nutritional needs. When examining iron specifically, women’s intake fell below recommendations regardless of dietary preference, with vegetarian and flexitarian diets presenting additional challenges. Gender dynamics significantly shape sustainable food practices beyond just nutritional aspects. The thesis corroborate that women typically lead household shifts toward climate-friendly diets while experiencing more complicated relationships with food choices compared to men. Paradoxically, despite consuming fewer resources and making more climate conscious selections, women experience a greater risk of nutritional deficiencies and health impacts when households transition to sustainable diets. The investigation of recreational athletes and young adults uncovered a clear relationship of dietary CO2e emissions to activity level, with CrossFit athletes exhibiting the highest CO2e emissions, followed by other highly-active individuals and moderately-active participants. The primary driver was not simply higher energy requirements but specifically how these needs were met, predominantly through animal-based protein sources. Yet high CO2e emissions was not inevitable. Several participants achieved notably lower CO2e while maintaining high performance levels through strategic incorporation of plant-based protein sources. These examples challenge the assumption that athletic performance necessarily demands a high environmental cost, suggesting that the barrier lies not in physiological requirements but in cultural norms and established beliefs about nutrition within sports communities. The findings question the assumption that low-carbon diets automatically promote health for all populations. The research shows that sustainable food systems require tailored approaches that consider gender-specific nutritional needs, diverse activity levels, and cultural contexts. The successful hybrid recipes and examples of low-CO2e athletic diets demonstrate that balancing environmental and nutritional goals is achievable with thoughtful planning. The path toward truly sustainable food systems must integrate bioavailability metrics into environmental assessments and address the social practices that shape our food choices. Only then can we create equitable transitions that protect both planetary boundaries and human wellbeing—especially for those leading the way in climate-conscious eating.