**Background:** Optimal nutrition in the preconception period can improve women's health and pregnancy outcomes. In South Africa, 64% of women have overweight or obesity, and 35% of households reported running out of money for food in 2021. The FIGO Nutrition Checklist was developed as a quick, cross-culturally applicable tool to identify nutritional issues. This study evaluated its implementation within the Bukhali trial in Soweto, a setting characterized by food insecurity, limited health literacy, and obesogenic environmental factors.
**Methods:** This adapted parallel mixed-methods study included 387 participants (291 nonpregnant, 96 pregnant) who attended a dietary counselling session with a dietitian between July 2021 and May 2022. Participants were women aged 18–28 years, predominantly with overweight or obesity (BMI >25 kg/m²). The dietitian administered the FIGO Nutrition Checklist, which includes six 'yes/no' diet quality questions about consumption frequency of meat/chicken, fruit/vegetables, fish, dairy, wholegrain carbohydrates, and packaged snacks/sugared beverages, plus lifestyle questions on folic acid, sun exposure, and iron levels. Quantitative data were analyzed using logistic regression to explore associations between participant characteristics and having a high-risk diet (>3 suboptimal practices, above the 50th percentile). Qualitative data came from in-depth interviews with the dietitian and 15 participants (convenience sample until saturation), analyzed using reflexive thematic analysis informed by the UK Medical Research Council process evaluation framework.
**Key Results:** Of 387 participants, 97.4% (n=377) answered 'no' to at least one diet quality question. The median number of at-risk practices was 3 (IQR 2–4). Only 33.3% met dairy recommendations and 39.4% met wholegrain carbohydrate recommendations. In logistic regression (n=384), food insecurity was positively associated with a high-risk diet (OR 1.87; 95% CI, 1.10–3.18; P=0.021). Graduating high school (OR 0.60; 95% CI, 0.37–0.95; P=0.028) and longer time enrolled in the trial (OR 0.96; 95% CI, 0.92–0.99; P=0.017) were inversely associated with a high-risk diet. Qualitative themes from the dietitian included ease of use, need for adaptations (translation, explanation of food groups), and benefits for personalized advice. Participants found the checklist acceptable and reported increased dietary awareness. Contextual barriers included food insecurity, social stressors, limited health literacy, and negative perceptions of BMI classifications ('obese' was described as 'painful'). Pregnancy provided motivation for healthier eating, but cravings and appetite changes posed challenges.
**Clinical Implications:** The FIGO Nutrition Checklist identified a very high prevalence of at-risk dietary practices in this South African population with overweight/obesity, similar to or higher than rates reported in Ireland (80%) and Hong Kong (95%). The checklist was acceptable and beneficial when administered by a dietitian, but contextual factors—particularly food insecurity, limited health literacy, and social stressors—must be addressed for effective implementation. The inverse association between trial enrolment duration and high-risk diet suggests the checklist may be useful for monitoring intervention impact. The authors recommend further research into use of the tool across South African healthcare settings, noting that implementation by community health workers or self-administration requires additional evaluation. The negative reactions to BMI classifications underscore the need for nonstigmatizing approaches in preconception and antenatal care.