Well......in school we had 8 hours of classes on Sundays. Massage class was always immediately after lunch, so half the class always went directly from lunch to the massage table.
We were taught that brittle diabetics should be told to check their levels more frequently after massage, to be sure to regulate as needed. It could go up or down. With the increased circulation, the meds also circulated faster - the blood sugar could lower too fast, then the meds be gone too quickly and the sugar level could raise quickly.
I have wondered if this was ever actually studied, though, or if it is theory, sort of like the concept that since massage increases circulation, people w/cancer should not be massaged or it could spread the cancer. That has been seriously rebuffed, for good reason. All the "could's" in the chapter on massage and diabetics made me question the validity. But - it is easy to remind diabetics to watch their levels more closely for a few hours, so I do. Nobody has ever questioned me on it yet, thank goodness, lol.
I prefer not to eat a heavy meal right before receiving a massage. I also do not want to be hungry. I want to be comfortable and not have to think about my belly, so that is what I advise, when asked.