Towards a Nigerian Nutrient Profiling System: Development, Validation, and Policy Application for Front-of-Pack Labelling

Nutrient profiling systems are scoring algorithms used to classify foods according to their overall nutritional composition, supporting applications including front-of-pack labelling, marketing restriction to children, and procurement standards. While multiple nutrient profiling systems have been developed internationally, none has been designed to reflect the nutritional composition of processed foods predominantly available in Nigeria or calibrated against Nigerian dietary guidelines and disease burden priorities. This thesis describes the systematic development, validation, and policy application of a Nigeria-specific Nutrient Profiling System for regulatory and public health applications. System development followed the World Health Organisation framework for nutrient profiling, incorporating four research phases. Phase one generated a comprehensive compositional database of 840 packaged processed foods available in Nigerian supermarkets and open markets across six states. Phase two applied an expert Delphi consensus process to identify nutrient criteria and threshold values reflecting Nigerian dietary patterns and health priorities, including hypertension, obesity, and anaemia as primary non-communicable disease concerns. Phase three validated the system against an independent expert panel's nutritional quality ratings (convergent validity) and against dietary intake and biomarker data from a nationally representative sample (criterion validity). Phase four simulated the regulatory and market impact of applying the system to front-of-pack labelling and child-directed food marketing restrictions. The Nigeria Nutrient Profiling System demonstrated strong criterion validity (sensitivity: 82 percent, specificity: 78 percent) and classified 54 percent of evaluated products as less healthy. Policy simulation indicated significant potential to shift purchase intent toward healthier options. Keywords: nutrient profiling, front-of-pack labelling, food policy, Nigeria, processed foods.