If I remember my health-nut mythology correctly, the theory is that inflammation (and especially inflammation related to blood sugar spikes) is believe to be a contributing factor to a lot of bad stuff: diabetes, cancer, aging, and so on.
Is daily inflammation a normal thing...? Maybe I'm just not observant enough, but I notice inflammation most often when I cut, bruise, scrape, or otherwise accidentally abuse my body - in which cases, memory tells me that (in the mild case) that's the right response.