Will eating candy with a lower ph than the stomach increase stomach acidity in the short term? The average stomach ph is 2.5. Some candies have a ph that is lower (more acidic) than that. Will eating candy with a lower ph than the stomach increase stomach acidity in the short term?

That's a simple closed chemical system, none of the fluid and reactant escapes, so yes, it will lower the pH of the stomach fluid, to add fluid with a lower pH.