Amah, was Pacquiao seen by a gastroenterologist, a doctor that specialized in the GI tract? Is he being treated holistically that aside from taking the prescribed medicines, there are things he can do not to aggravate his ulcer like not ingesting alcohol, not eating fatty or acidic foods like tomatoes and pineapple; also, he is not to take aspirin (salicylic acid) but if he must take aspirin for pain relief, to take only the enteric coated ones that do not dissolve readily in the stomach but slowly down the tract.
That acid reflux, is there weakness in his LES (lower esophageal spinchter) that it cannot keep gastric acid down? Is his vagus nerve hyperactive and cause the stomach to overproduce gastric acid?
Nowadays, many would refute that skipping or not eating meals on time is the cause of stomach ulcer. Those with anorexia nervosa that starved themselves, and those that do not eat regular meals because of poverty or whatever, heart failure is often the cause of their morbidity, their bodies severely weakened by malnutrition, rarely had they stomach ulcer.
If Pacquiao has recurring gastric reflux, or stomach ulcer, there's an infectious bacteria called Helicobacter pyllori, or H. pyllori, it may be a precipitant. H. pyllori can be killed by antibiotics. Interestingly, it has been found that 90 % of those with Peptic Ulcer Disease, and 70% of gastric ulcer sufferers have H. pyllori infection.
A gastroenterologist who is up to date with studies and new developments should be able to explain all.