We report an interesting finding that the catalytic performance of supported Ni/γ-Al2O3 catalyst towards selective catalytic hydrogenation of edible oils can be greatly enhanced by pretreatment of the γ-Al2O3 support before catalyst preparation. Calcination of Al2O3 at appropriate temperatures results in the highly dispersive nano Ni/γ-Al2O3 catalyst and thus improves the catalytic performance. Catalyst sample of improved physical properties prepared by modified procedure using γ-Al2O3 as support was characterized using powder XRD, SEM, BET, FTIR, Particle size analyzer, CO-chemisorption, and TPR studies. These studies indicate that support pretreatment results in enhancing catalyst dispersion with increase in Ni loadings. Clearly the effect of surface area and particle size of the catalyst coupled with surface properties and method of catalyst preparation on the saturated fats content of the foods like margarines prevails.