The dominance in your metabolism can either be attributed to the sympathetic or parasympathetic part of your autonomic nervous system or whether you oxidize or burn energy fast or slow. Once aware of this dominance, food can be consumed that benefits the individuals specific metabolism.
Fast oxidizers and parasympathetic dominant people should eat a diet that is higher in protein. Slow oxidizers and sympathetic dominant people should eat a diet that is higher in carbohydrates.
For more information check out http://www.metabolictyping.com/