There are three main ingredients in jam: fruit, pectin and sucrose (table) sugar. When the three ingredients are heated together, the sugar molecules link onto water and allow the pectin to form a gel consistency typical of jam.
Since fruit contains a natural sugar called fructose, a fruit jam cannot be completely sugar-free. However, it can be reduced sugar or no added sugar.
Lower sugar jams will still require some form of sugar to attain a similar jam consistency. Often sugar substitutes (like stevia) or sugar alcohols (like sorbitol) will be used instead of sugar.
Most sweeteners and sugar substitutes (see Sugar substitutes) will contain no carbohydrate and therefore have no glycaemic load (no rise in blood glucose). Sugar alcohols have different glycaemic loads and therefore can affect blood glucose differently.
Always look at the label to what is providing the carbohydrate to decide whether it’s a good choice.
Carbohydrates coming from a safe sugar substitute (aspartame, stevia, etc.) or sugar alcohol (like sorbitol, erythritol, xylitol, mannitol, etc.) will provide carbohydrate in the product but will have a small effect on blood glucose.
For example, a standard All Gold Strawberry Jam provides 57g of carbohydrates as per the label. Thistlewood No Added Sugar Raspberry Jam provides 30g of carbohydrate as per the label.
The first three ingredients in the regular jam are glucose, strawberry and cane sugar.
The first three ingredients in the no added sugar jam are raspberries, sorbitol syrup, and water.

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