Why Do We Eat? A Neurobiological Perspective. Part III

In the first post, I explained that all voluntary actions are driven by a central action selection system in the mesolimbic area (the reward system).  This is the part of you that makes the decision to act, or not to act.  This system determines your overall motivation to obtain food, based on a variety of internal and external factors, for example hunger, the effort required to obtain food, and the sensory qualities of food/drink.  These factors are recognized and processed by a number of specialized 'modules' in the brain, and forwarded to the reward system where the decision to eat, or not to eat, is made.  Researchers divide food intake into two categories: 1) eating from a true energy need by the body (homeostatic eating), e.g. hunger, and 2) eating for other reasons (non-homeostatic eating), e.g. eating for social reasons or because the food tastes really good.

In the second post of the series, we explored how the brain regulates food intake on a meal-to meal basis based on feedback from the digestive system, and how food properties can influence this process.  The integrated gut-brain system that accomplishes this can be called the satiety system.

In this post, we'll explore the energy homeostasis system, which regulates energy balance (energy in vs. energy out) and body fatness on a long term basis.

The Energy Homeostasis System

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