Sugar free or 

      No added sugar 

These are two very different things. Even if 
no sugar is added, it does not mean that the 
body does not have to process glucose, as 
carbohydrates are converted into glucose.
That is why we always talk about "sugar-free" 
when it comes to keto, LCHF or low-carb.
We therefore reduce carbohydrates to a very 
small minimum.
But is that healthy in the long term? ... yes, 
of course, as carbohydrates are not essential 
for our body.

I like to call it: 
"species-appropriate nutrition"