This paper represents the third in the series of designed to explore the scope and contributions of computerized diets to the overall improvements in the technical and economic efficiency in the pig industry. The present paper attempts to establish the functional relationships between the principal nutrient components (Protein and energy) of weaners’ diets on weight gain, feed utilization and carcass quality. The established functional relationship was used as a basis for incorporating animal performance into feed formulation activities while using linear programming techniques to derive expansion path diets. Cumulative feed intake was positively related to liveweight gain in weaner pigs. While protein and energy intakes are significant explanatory variable, they explained only 37 and 36 percent, respectively, of the total variations in liveweight gain. No significant relationship was found between carcass quality and protein and energy intake levels for pigs of the weight range studied. While it was clearly demonstrated that the formulation of expansion path diets using liner programming techniques could be used for selecting cost diets to achieve different weekly liveweight gains, its practical application must await result of animal feeding trials designed to test the performance of the derived expansion path diets