Literature suggests that a varied and high-quality diet is essential for adequate nutrient intake and improved health outcomes. Despite this knowledge, and considering that agricultural participation can enhance food availability and diversity, populations continue to face challenges in achieving dietary diversity due to socioeconomic constraints among a plethora of factors. Understanding this relationship becomes particularly important for Lesotho, where such insights can inform strategies to promote dietary diversity, improve public health, and reduce healthcare costs. This study utilized data from the Household Budget Survey to examine how household food consumption patterns, socioeconomic factors, and agricultural participation influence food diversity and health-related costs. Using Partial Least Squares-Structural Equation Modeling (PLS-SEM), we analyzed the relationships between these variables to gain a nuanced understanding of their interplay. Results reveal that food diversity is shaped by multiple factors, including agricultural participation, which directly affects health outcomes. Household characteristics, such as income, household size, and education level of the household head, significantly predict both food diversity and health expenditure. These findings underscore that supporting agricultural engagement and promoting dietary diversity can be cost-effective strategies to improve nutrition and reduce healthcare costs in Lesotho. Policymakers should focus interventions in these areas.