Allostasis is the efficient regulation required to prepare the body to satisfy its needs before they arise by budgeting those needed resources such as oxygen, insulin etc., as opposed to homeostasis, in which the goal is a steady state. Allostasis, stability through variation, was proposed by Peter Sterling and Joseph Eyer in 1988 as a new model of physiological regulation. The goal of every living being is to “find and maintain a steady state for survival” which is achieved through allostasis and homeostasis. The term allostasis is used more frequently now since it is more inclusive of the idea that not everything in the body is in a single steady state meaning that there are varying levels of energy. Evolution and allostasis A second perspective on allostasis is that it is included in the story of how the brain was created. Barrett argues that during evolution organisms' internal systems became much more advanced; continuing to just have several groups of cells would have poorly managed these new systems that these bodies were acquiring. A brain was needed instead because its large size is much more capable of efficient management. However, in rare cases animal species do not rely on brains nor a similar allostatic process. The sea squirt is one example because once the larvae have fully grown they “absorb their brain.” The sea squirt's allostatic process would not be as complex as a human's for example since both species have ecological niches that are of different complexities (i.e. ”All animals have brains that are adapted to their environmental niches and life cycles”). Etymology Allostasis was coined from the Greek ἄλλος (állos, "other," "different") + the στάσις (stasis, "standing still"). The concept was named by Sterling and Eyer in 1988 to mean "remaining stable by being variable". Nature of concept Allostasis proposes a broader hypothesis than homeostasis: The key goal of physiological regulation is not rigid constancy; rather, it is flexible variation that anticipates the organism's needs and promptly meets them. Rather than simply responding to the environment, allostasis utilizes predictive regulation, which has a more complex goal in evolution of adaptation by changing based on what it anticipates, rather than by staying the same or "in balance" in response to environmental changes, as homeostasis suggests. This places homeostasis as a function within allostasis; however, some argue it is a larger paradigm altogether. Allostasis redefines health and disease beyond the