It's possible that obesity and dietary patterns that are high in saturated fats cause changes in glutamate and GABA metabolism and neurotransmission, as has been shown in animal studies.

while restoring glutamine and glutamate levels to normal. “These data suggest that BPTES regulates glutamine metabolism ...

Urinary glutamate enrichment was not detected ... To our knowledge, this is the first multistable isotope study quantifying the metabolism of arginine in enterally fed human preterm infants.