It took me decades but I figured out that "it isn't sugar, its carbs(potatoes, corn, rice, pasta, etc, etc....." is bullshit when it comes to carbs. With the exception of insoluable fiber, carbs are effectively sugar.  They impact blood glucose generally to the same extent.  The discussion of glycemic index is IMHO inconsequential to blood glucose impact though lower glycemic index foods impact my BG more slowly, in my experience and according to the countless hundreds of thousands of blood glucose tests I have given yself and the many years of a Continuous Glucose Monitor stuck in my body has proven this beyond a shaddow of a doubt.

Another interesting factoid I have proven with my own body is... calories do not make you fat.  Blood glucose makes you fat.  Eating nothing but lard, will be a huge caloric intake but it will not make you fat.  Dietary fat does not turn to blood glucose.  So, it cannot be stored as fat.  Protein does impact blood glucose though due to the human digestive system only a very small % of protein intake turns to blood glucose. This is why high fat, high protein, low carb diets work for losing and maintaining weight.

So, I eat meat, I eat fats, and I eat leafy green veg, and a few verifiably low CHO veg (califlower, broccoli, etc....).  I test every thing I consume against my blood glucose response.  There are some very good alternatives and subsititues for high CHO foods.  My current favorite is Shiritake or Konjac noodles.  They give a mostly pasta like experience without discernable impact to my BG.

My way is not THE way, it is A way for managing to normalized Blood Glucose levels.  But for sure processed foods tend to be huge carb bombs.  So, I read the labels and maintain clarity that w5g hat matters predominantly is the serviing size. Something that shows carb content as  5g/serving may on the surface look like it is low or moderate carbs.  When you look at the serving size and it is "2TBSP" reality is that it is a sugar bomb.  

Knowledge is power over (this/my) disease. Awareness of the full picture combined with knowledge is mastery.

Use your Docs as your team and make sure they deliver to your expectations. Regardless of what disease or health issues are in play.

In my laymans opinion of course.

The comment about "how come people didn't used to have gluten issues" and your analysis and answer are very comprehensively applicable to many diseases that are prominant today that were rare historically.  Take my disease for example.  T-1 diabetis has exploded over the past 100 years and is accelerating in prominancy.  Because prior to the 1920s a Dx of T-1 was a death sentense with survival rarely exceeding 90 very miserable torturous days from onset.  It was rare for adults to have T-1 so the passing on of the genes was very limited.  Today, T-1s can live extended lives, have kids, and propegate the disease far, wide, and into future generations.

Don't get me wrong. I am happy to have a life at all. I am a miracle of modern pharmaceutical science.  Though I did not make this decision as a young man, I did decide in my 30s that I did not want to give this disease to my children. So, that is one reason why I don' have any BKs.  The primary reason is that I was not willing to risk my bride's health and life by creating a sweet (pun intended) spawn of Rags.  SS nearly killed her (Pre-eclampsia/Toxemia) and lady Docs strongly advised that she not have any more kids.

I have an incredible son. Who is free of this disease.  Though apparently he does have a gluten issue.  But his mom and I did what we could to make sure he overcame the shit shallow and polluted end of his gene pool as far as honor, character, and life performance are concerned.  The rest, is somewhat of a crap shoot for everyone.