The proliferation of “sugar free” and “no sugar added” foods has created a great deal of confusion. Many of these products are NOT safe for diabetics and low-carbers.
Take, for example, “no sugar added” ice cream. The manufacturer may substitute an artificial sweetener for sugar in the recipe, and thus he is not “adding any sugar”. However, he is making the product with milk, which contains lactose, a type of sugar.
Or take the hard candy touted as “sugar free” that is actually made with fructose. While not quite as bad as refined ‘table sugar” it is really not very different in terms of carbohydrates and calories.
As for “sugar free” canned fruits, most of them are sweetened with concentrated grape or apple juice and are certainly not low carbohydrate.
Your best defense is to read product labels carefully. A manufacturer can disguise sugar by calling it sucrose, corn syrup, dextrose, or a dozen other names and technically NOT be adding sugar – at least not refined table sugar. And think carefully about “no sugar added” labels; this does NOT mean that the base product is sugar free, only that no additional sugar has been used – and that’s a big difference.