Autonomic Nervous System in the Control of Energy Balance and Body Weight: Personal Contributions

TLDR

Obesity prevalence is rising worldwide, prompting WHO to label it a pandemic, and the autonomic nervous system—particularly sympathetic activity—plays a key role in energy balance and body weight regulation, as highlighted by the Mona Lisa Hypothesis. This review synthesizes the authors’ data and perspectives on how autonomic nervous system activity influences energy expenditure and food intake, including parasympathetic effects on energy consumption. The authors analyze autonomic nervous system influence on energy expenditure and food intake, summarizing their own data and perspectives. Sympathetic activation raises energy expenditure and lowers food intake, while weight loss reduces sympathetic activity; increased parasympathetic activity can paradoxically boost energy consumption.

Abstract

The prevalence of obesity is increasing in the industrialized world, so that the World Health Organization considers obesity as a "pandemia" in rich populations. The autonomic nervous system plays a crucial role in the control of energy balance and body weight. This review summarizes our own data and perspectives, emphasizing the influence exerted by autonomic nervous system on energy expenditure and food intake, which are able to determine the body weight. Activation of the sympathetic discharge causes an increase in energy expenditure and a decrease in food intake, while reduction of food intake and body weight loss determines a reduction of the sympathetic activity. On the other hand, pathophysiological mechanisms of the obesity involve alterations of the sympathetic nervous system in accordance with the "Mona Lisa Hypothesis," an acronym for "most obesities known are low in sympathetic activity." "Furthermore, the parasympathetic influences on the energy expenditure are analyzed in this review, showing that an increase in parasympathetic activity can induce a paradoxical enhancement of energy consumption.