Several proteins in the bakers yeast, Saccharomyces cerevisiae, have counterparts in humans with conserved function and regulation. The metabolic pathways in which these proteins participate are usually essential for a continued robust performance by the cells. In humans, a malfunction in the regulation of these pathways triggers metabolic imbalance and eventually leads to disease. For practical and ethical reasons, it is not feasible to study the dynamic processes of disease mechanisms in humans and therefore, model organisms such as mice, fruit flies and even bakers yeast, are employed to understand these processes. Although, multicellular model organisms offer the advantage of evolutionary proximity to humans, it is not possible to rapidly quantify the dynamic phenomena of molecular interactions. We studied the impact of dynamically changing nutrition environments on the cellular energy level and how this controls various aspects of metabolism in S. cerevisiae. Our focus was on the homeostasis of cellular energy by the highly conserved AMP-activated protein kinase and its control of lipid metabolism. Our results indicate that despite being a unicellular organism, the regulation of cellular energy content and lipid metabolism is highly conserved compared to human, and that the yeast system makes a useful model for studying the molecular mechanisms of the metabolic syndrome as well as for screening new drug candidates and discovering new drug targets.