The Control of Physiology Over Eating

Most of us attach some importance to what we choose to eat. But in fact, eating is not entirely a matter of conscious choice. Like breathing, it is a physiological necessity for life. So if you dig a little, it becomes clear that physiology exerts considerable control over our eating behaviors.

Over the last three decades, the scientific understanding of this control of eating by our physiology has grown into a “vast literature,” say Alan Watts and colleagues in a new review paper. This is science that deserves your attention if you want to understand obesity and related diseases, say the authors:

“How eating behaviors are controlled by physiological systems is at the heart of understanding the
etiologies of metabolic diseases. This review addresses the way physiological signals from the
gastrointestinal tract, adipose tissue, pancreas etc. engage sets of interacting neural networks
located throughout the brain to enable the complex motor events that lead animals to eat.”

Building on Clinical Observations

Though much of this science is new, the clinical insight is not. More than a century ago, clinicians saw that damage to the hypothalamus could lead to big changes in eating behaviors. So in the 1930s, scientists started to experiment in animals. The point was to understand how this part of the brain could control a seemingly voluntary behavior.

Then in 1960, Sebastian Grossman discovered that injecting certain molecules into the hypothalamus could stimulate eating or drinking. It was crude, but it was an important spark for research. From there, a long line of research followed. It brought a long list of neurotransmitters and peptides into view. Eventually, it became clear that this part of the brain was trading signals with other parts of the body.

More Networked Than Centrally Controlled

All of this may have started with the hypothalamus. But eating is a complex behavior. So the physiology that controls it requires the interaction of neural networks throughout the brain and the body. These networks interact with the gastrointestinal tract and much of the body to regulate eating. You are what you eat might actually mean you eat what you are.

This review by Watts et al is a treasure trove that will take many readings to digest. However, one thing is immediately clear. Eating is not a simple voluntary behavior. And thus, when obesity develops, it is largely the result of physiology interacting with our environment.

The choice we have to make is how we shall respond to these facts and thus adapt for better health.

To consume this “tour de force” by Watts et al, click here.

The Bean Eater, painting by Annibale Carracci / WikiArt

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October 25, 2021