What role does MSG play in obesity and fatty liver disease?

The commonly used food additive monosodium glutamate (MSG) has been
linked to obesity and disorders associated with the metabolic syndrome
including progressive liver disease. A new study that identifies MSG as a
critical factor in the initiation of obesity and shows that a
restrictive diet cannot counteract this effect but can slow the
progression of related liver disease is published in Journal of Medicinal Food.

 Here's the paper

A Dietary Restriction Influences the Progression But Not the Initiation of MSG-Induced Nonalcoholic Steatohepatitis