The hypothalamus is a critical part of the brain, often referred to as the 'vegetative brain', that regulates physiological functions including blood pressure, body temperature, body weight, and blood sugar control.

“it's the very small organ or at least it's a very small part of brain about the tip of the small finger but does play a role in the regulation of many important physiological functions including things like blood pressure or body temperature and from my point of view very importantly body weight and also increasingly apparent that it plays an important role in blood sugar control as well so it's been known for many many years as being a critical part of the brain the so called vegetative brain not under conscious control”