Obesity and Type 2 Diabetes Mellitus Explained by the Free Energy Principle

The principle of 'brain energy on demand' and its predictive power for stress, sleep, stroke, obesity and diabetes

Does the brain actively draw energy from the body when needed? There are different schools of thought regarding energy metabolism. In this study, the various theoretical models are classified into one of two categories: (1) conceptualizations of the brain as being purely passively supplied, which we call 'P-models,' and (2) models understanding the brain as not only passively receiving energy but also actively procuring energy for itself on demand, which we call 'A-models.' One prominent example of such theories making use of an A-model is the selfish-brain theory. The ability to make predictions was compared between the A- and P-models. A-models were able to predict and coherently explain all data examined, which included stress, sleep, caloric restriction, stroke, type-1-diabetes mellitus, obesity, and type-2-diabetes, whereas the predictions of P-models failed in most cases. The strength of the evidence supporting A-models is based on the coherence of accurate predictions across a spectrum of metabolic states. The theory test conducted here speaks to a brain that pulls its energy from the body on-demand.

Association of Obesity with Coronary Artery Disease, Erosive Esophagitis and Gastroesophageal Reflux Disease: A Systematic Review and Meta-Analysis

BACKGROUND

We aimed to determine the plausible role of high body mass index (BMI) in the etiopathogenesis of coronary artery disease (CAD), erosive esophagitis (EE) and gastroesophageal reflux disease (GERD) and their complex associations.

METHODS

The published literature was retrieved from Cochrane, Google Scholar, Embase, PubMed and Scopus databases until August 2021 based on the inclusion and exclusion criteria. The Newcastle-Ottawa quality assessment scale was used for the risk of bias and publication bias with a funnel plot. Heterogeneity between studies underwent evaluation using the I ² statistic and Q-test, and a random and fixed-effect model analysed studies with low to moderate heterogeneity.

RESULTS

Out of 3819 studies extracted, 20 studies were studied based on the inclusion and exclusion criteria. The study corroborated the direct association of GERD symptoms and EE among obese Odds Ratio (OR) = 4.25) and overweight subjects (OR 9.75). Separate analyses of the link between GERD symptoms and EE was conducted among the overweight (OR 4.11, OR 4.61) and obesity subjects was statistically significant (OR 12.07, OR 9.95). The corresponding adjusted OR was noted for the association of CAD with overweight and obesity amounted to 3.41 and 3.01, respectively. Separate subgroup analysis was analyzed based on different ethnic populations for the association between GERD symptoms and EE in obesity (OR of 9.38) and over-weight (OR of 4.21) subjects were statistically significant (P<0.05). For population subgroup analyses the overall OR of 3.32 was noted on the association between CAD and obesity.

CONCLUSION

Moderate to severe BMI has bene considered as an independent risk factor for GERD symptoms, EE and CAD.