The body maintains circulating glucose at the highest safe level (around 80-100 mg/dL fasting) because circulating glucose is valuable for energy production, despite the risk of glycation above this point.

“the system has been built to have about the most circulating glucose that you can have safely right and i think a lot of the really important metabolites have been kind of pushed to the edge this way right and so we know that there are deleterious you know protein modification reactions like oscillation reactions that occur when glucose gets above this point so we kind of in evolution pushed right up to the highest and non-problematic glucose we didn't do that for a lot of other metabolites and that's why there's not a lot of you know part of why there's not a lot of other diseases like diabetes”