INTRODUCTION:
International evidence suggests that food-related marketing shapes food choices in resource constrained communities by exploiting culture and economic vulnerability, limiting perceived options, and normalizing unhealthy diets.

METHODS:
This study examined how informal food businesses (spaza/convenience shops) have the potential to influence food choice patterns through the advertising of unhealthy foods in three resource-constrained South African townships. Outdoor food advertisements displayed on shop walls and within business yards were systematically and geospatially mapped using the Quantum Geographic Information System software, coded as healthy and unhealthy food and analyzed quantitatively and qualitatively to present the prevalence of the food type, visual elements, and language to identify dominant themes and marketing strategies.

RESULTS:
Of the 690 outdoor food advertisements mapped, 27% were located either on external, public-facing walls of spaza/convenience stores or within informal business yards. Advertising predominantly promoted unhealthy and processed foods and emphasized affordability through culturally and socially resonant messaging. Other emerging common themes included convenience and socio-cultural desirability, framing inexpensive fast foods as satisfactory and appealing. These strategies appeared to target household food decision-makers, reinforcing unhealthy food choices within constrained socioeconomic contexts.

CONCLUSIONS:
The findings highlight how food marketing in informal retail spaces intersects with culture and socioeconomic conditions to shape food choices, potentially reinforcing dietary inequalities and adverse public health outcomes in marginalized urban communities. Coordinated policy interventions and community based strategies that restrict food business’ practices of marketing unhealthy food and improve access to healthier options are urgently needed to promote fairer, healthier urban food system.