Introduction: Diet quality constitutes a fundamental dimension of food security and plays a critical role in shaping public health outcomes, labor productivity, and the sustainability of rural livelihoods. Unlike calorie-based measures, diet quality reflects the adequacy and balance of macro- and micronutrient intake, which are essential for preventing malnutrition and nutrition-related diseases. Recent research increasingly emphasizes that disparities in diet quality are not merely the result of individual or household-level factors, but are deeply embedded in broader socioeconomic structures and spatial contexts. Unequal access to resources, differences in food production systems, market integration, and regional economic conditions contribute to heterogeneous nutritional outcomes across regions. In many developing and middle-income countries, including Iran, rural areas occupy a paradoxical position. While they are the primary centers of food production, they often experience heightened vulnerability to poor diet quality due to structural transformations in food systems, declining diversity of local production, rising dependence on food markets, and increasing food prices. These changes have altered traditional rural consumption patterns and, in some cases, weakened access to nutrient-rich foods. Despite relatively adequate national food availability, significant interregional disparities in diet quality persist, particularly in rural areas. In Iran, most empirical studies have focused on general food security indicators, poverty, or calorie intake, with limited attention to multidimensional diet quality and its spatial and structural determinants. Moreover, few studies have employed an integrated analytical framework that simultaneously considers nutritional indicators, socioeconomic structures, and spatial patterns. This study aimed at addressing this gap by providing a comprehensive spatial and structural analysis of diet quality in the rural areas of Iran at the provincial level.
Materials and Methods: This study was based on provincial-level data for the rural areas of Iran from 2024, obtained from official statistical sources. Diet quality was assessed using eight nutritional indicators, including calorie intake, carbohydrates, protein, iron, calcium, and vitamins A, B1, and C. These indicators capture both macronutrient sufficiency and micronutrient adequacy, allowing for a multidimensional evaluation of dietary quality. In addition to nutritional variables, a set of rural socioeconomic indicators was incorporated to examine the structural context of dietary outcomes. These indicators reflect agricultural production capacity, income inequality, food expenditure pressure, and overall rural economic conditions. The empirical analysis was conducted in three sequential steps. First, Principal Component Analysis (PCA) was applied to the eight nutritional indicators to reduce dimensionality and extract latent structures underlying dietary consumption patterns. PCA enables the construction of a composite index that summarizes the common variation across multiple nutrients and avoids issues of multicollinearity. Second, the spatial distribution of the extracted composite diet quality index was examined using the global Moran’s I of Moran’s Global Spatial Autocorrelation (MGSA) to assess the presence of spatial autocorrelation across the provinces. This test evaluates whether the provinces with similar levels of diet quality tend to cluster geographically. Third, a multivariate cluster analysis was performed by combining the composite diet quality index with selected socioeconomic variables. This approach was used to classify the provinces into structurally homogeneous groups based on the interaction between diet quality, agricultural production, income distribution, and food expenditure dynamics.
Materials and Methods: This study is based on provincial-level data for rural areas of Iran for the year 1403 (2024), obtained from official statistical sources. Diet quality is assessed using eight nutritional indicators, including calorie intake, carbohydrates, protein, iron, calcium, and vitamins A, B1, and C. These indicators capture both macronutrient sufficiency and micronutrient adequacy, allowing for a multidimensional evaluation of dietary quality. In addition to nutritional variables, a set of rural socioeconomic indicators was incorporated to examine the structural context of dietary outcomes. These indicators reflect agricultural production capacity, income inequality, food expenditure pressure, and overall rural economic conditions. The empirical analysis was conducted in three sequential steps. First,

Results and Discussion: The PCA results indicated that the first principal component (PC1) explained a substantial proportion of the total variance in the nutritional indicators. The PC1 exhibited strong positive loadings for most macro- and micronutrients, suggesting that it would effectively capture the overall dietary adequacy. Accordingly, this component was interpreted as a composite “Diet Quality Index” representing the general nutritional status of rural households across the provinces. The spatial analysis revealed pronounced interprovincial variation in the Diet Quality Index. However, the Moran’s I did not indicate statistically significant spatial autocorrelation. This finding implied that the provinces with similar levels of rural diet quality did not systematically cluster in geographic space; in other words, the dietary disparities across rural Iran could not be adequately explained by spatial proximity alone. This result highlighted the limited explanatory power of purely geographical factors and underscored the importance of structural and socioeconomic determinants. The multivariate cluster analysis further elucidated the structural nature of dietary disparities by identifying three distinct groups of provinces. The first cluster comprised the provinces characterized by relatively high diet quality despite moderate- or low-income levels. In these areas, stronger local agricultural production, higher self-consumption of food products, and more traditional dietary patterns appeared to mitigate economic constraints and supported better nutritional outcomes. This finding suggested that local food systems and production diversity could play a compensatory role in sustaining the diet quality. The second cluster included the provinces with lower diet quality, high food expenditure pressure, and greater dependence on market-based food systems. In these regions, weaker local production capacity and higher exposure to food price volatility appeared to negatively affect the dietary quality, even when average income levels were not particularly low. This pattern reflects the vulnerability of market-dependent rural households to economic shocks and rising food costs. The third cluster consisted of the provinces with relatively higher levels of economic development but mixed dietary outcomes. In these provinces, increased market integration and dietary transition processes did not necessarily translate into the improved diet quality. This finding suggested that economic development alone was insufficient to guarantee better nutritional outcomes and might, in some cases, coincide with the reduced dietary diversity and declining intake of nutrient-rich traditional foods. Overall, the combined results demonstrated that the rural diet quality in Iran was shaped by complex interactions between production structures, market dynamics, and socioeconomic conditions rather than by income or spatial location alone. The absence of spatial clustering reinforced the argument that the nutritional inequalities were fundamentally structural in nature.
Conclusion and Suggestions: This study provided a comprehensive spatial and structural assessment of the diet quality in rural areas of Iran using a multidimensional analytical framework. The study findings revealed that the rural diet quality was not primarily determined by the geographical location or income levels, but by the interaction of structural, economic, and production-related factors. From a policy perspective, the results emphasized the need for targeted, cluster-based nutrition strategies rather than uniform, geographically defined interventions. Strengthening local agricultural production, promoting diversified rural food systems, reducing income inequality, and alleviating food expenditure pressures should be central components of nutrition policy. Policies that reinforce local food systems and improve sustainable access to nutrient-rich foods can enhance the effectiveness of food security interventions and contribute to more equitable and resilient rural development in Iran.