The purpose of this review is to summarize what we know about preimplantation embryo metabolism, focusing on ruminant species, and to discuss how this knowledge informs our approach to culturing embryos in vitro. The important relationship between embryo metabolism and viability will be emphasized, and theories of metabolic networks in embryos presented. Methods that have historically been used to study embryo metabolism will be compared and contrasted to a new method of evaluating embryo metabolism; metabolomics. Finally, the advantages and disadvantages of using metabolomics technologies to study embryo metabolism will be critically evaluated. The application of metabolomics to assisted reproductive technologies, and specifically to embryo culture, will be highlighted. We conclude that use of metabolomics to study embryo physiology will enlighten our understanding of embryo metabolic pathways in the context of a complete media that enables good blastocyst production. This way of thinking about embryo metabolism as dynamic, complex and interrelated biochemical pathways, informed by metabolomics, will allow us to develop the next generation of embryo culture medium to support and manipulate metabolism to promote embryo viability, as well as to identify the most viable embryos for transfer.