Its like with an older car: the tires are not new anymore, the bumpers dented, the shock absorbers squeal and the motor is oily.
There is no One-Fix for that.
With gastritis you very probably have the Helicobacter Pylori, which sits in the stomach lining and conceals itself from acid by producing a protective layer. There is no use eradicating the Helico if it reinfects from the liver/gall again. therefore a bigger cleanup may be of quite some value:
parasite cleanse, Liver cleanse while zapping. Zapping strengthens the immune system.
For me the greatest effect was from parasite cleanse, I gained 5 kg thereafter (being always meager), but the shelters for the Helico in the liver should be swept out with a liver cleanse also. I felt very new after that. 1000 Stones out in 8 cleanses.