Life runs on many thousands of different chemical reactions, known collectively as cell metabolism. Metabolic reactions are vital for keeping cells and organisms growing and alive, and problems with cellular metabolism are implicated in ageing and diseases such as cancer, diabetes and brain disorders. Rather than thinking about cell metabolism as a collection of individual reactions, we are working to understand metabolism as a dynamic, interconnected network of processes that adapts in response to changes and stresses in the environment, and that evolves and functions as an entity. In the Starling Medal lecture, Ill summarize our efforts in using yeast as a simple system for conducting hundreds to thousands of analytical measurements, allowing us to study how these complex metabolic processes are controlled, and how they are reconfigured in response to environmental changes. By taking detailed precision measurements of the genes and molecules involved in metabolic processes and putting the data into computer analysis programmes, we can see how the cells metabolism adapts and changes in response to various stresses and strains. And we can also see what happens when crucial parts of the system are altered or faulty, as a model for human diseases, as well as derive the very basic principles of metabolism, like the ones that enabled its origin in early evolution.