pH varies throughout your body and is closely regulated by multiple homeostatic processes. Acid base balance is well understood physiology. It’s not a good idea to try to alter your acid base balance unless advised by a medical professional. Most attempts at altering pH with diet does little more than change urine pH.
Your body will self adjust to app 7.4 with a healthy diet and no illness. Use ph strips if you feel the need to know. I know people with serious chronic conditions that regulate their diet by how acidic they are each day but that is due to a chronic pathological condition.