How recent was Max's last fecal exam from the vet?
How long has he been eating his current food?
Is the stool regular in color?
How long has he had the frequent bowel movements?
Okay, thank you for that information.
I would probably take a stool sample in a ziploc (a loose one) to your vet for a fecal analysis. This will only cost ablout $15 and if this is the problem it will save you a lot of time and money trying to help him.
Short of that, I would definitely try him on a different food just to see. There are several foods out there for sensitive stomachs such as Iam's Sensitive Stomach, Purina HA and most of the upper end brands will have some form of "sensitive stomach" diet. I would try this just to see if it helps. Some dogs with inflammatory bowel can respond well to a diet that is formulated for the sensitive GI tract. You can also try adding some fiber to his food. You can do this by adding a tablespoon daily of metamucil or benefiber. You can alternatively use canned pumpkin.
Please let me know if you have more questions,