I was recently reminded that agave syrup tends to have a very high fructose/glucose ratio. Since I found that pure glucose (from brown rice syrup) gives me worse problems than RF honey, fruits or starchy foods, I suspected that fructose is less of a problem for me and realized that agave syrup is a way to test that (yes, I know it's not raw Paleo, I only used it for testing, not to make it part of my diet). Sure enough, I tried consuming the equivalent amount of carbs from agave syrup and didn't have any significant negative symptoms, unlike the rice syrup. Not surprisingly, my blood glucose didn't spike up with the agave syrup like it did with the rice syrup, which is a known difference.
My BG was actually down 10 mg/dl an hour after consuming the agave syrup. Oddly enough, I actually felt rather good and my appetite improved (which would be a problem for someone trying to lose weight, but a benefit for someone like me who would be happy with some increased appetite to bulk up a bit). Instead of my teeth getting scummy like they do after eating glucose, they actually felt a bit cleaner soon after eating the agave syrup. The good feeling and cleaner teeth were surprises for me, given all the demonization of fructose in the Paleosphere. Excess fructose tends to cause problems in the liver, so it may be that there were negative effects that I just can't see or feel.
So this seems to be the ranking of types of carbs for me, from best to worst:
- resistant starch (it's actually more like a fat than a carb, since gut bacteria convert it into SCFA's) -- produces mostly benefits; only problem is the minor nuisance of excess flatulence if I accidentally overdo it
- fructose -- no noticeable problems and possibly some mild benefits
- easily-digestible starch -- mild to moderate negative symptoms
- glucose -- moderate to severe negative symptoms, such as dramatic spikes in BG
This doesn't fit with popular assumptions in the Paleo sphere, which had me suspecting fructose more at first, until my personal testing showed otherwise. I suspect that "pyroluria" may have something to do with this. On the bright side, resistant starch seems to be reducing the severity of all the negative symptoms I get from glucose, not just improving my blood glucose readings. Time will tell.