Crossfitters and others connected to the zone diet often acknowledge the negatives of eating easily-digestible carbs.

What, in particular, is more dangerous about sugar itself, as compared to other easily digestible carbs?

Not really much difference. In fact sugar (sucrose) rntwrs the bloodstream more slowly than some other carbohydratw foods because it is composed if both glucose and fructose and has to be broken down first in the body.

Bryan, sugar still does break down quite fast, compared to other more zone-favorable carbohydrates, i.e. the carbohydrates in veggies and fruit. I don't know if one can claim that sugar is any more dangerous than other easily digestible carbs (zone-unfavorable), I think it is equally as dangerous.

Straight sugar is only one step away from being converted into glucose, and thus enters the bloodstream quickly, which leads to a spike in blood sugar, resulting in a spike in insulin levels to control the glucose levels.

On the other hand, when a whole food is eaten, the glucose is converted much more slowly during the digestion process because there are more steps to go through in the conversion. This results in a more moderate rise of glucose and a more moderate insulin response. Less peaks and valleys.

Our body convert all of meal we eaten into glucose,but there is an important difference between sugar and other food which have enzymes,amino acid,vitamin's and minerals on the other hands sugar has none of those which is dangerous for our bodies health,sugar puts our body towards nutritional disadvantages.

We can still consume sugar but we must consume at the very minimal quantity as too much is really not good for our body and health.