Do "Sugar-Free" Sweets Raise Blood Sugar? The Net-Carb Myth

Diabetes Myths · 2 · June 27, 2026

A post in a diabetic recipes group celebrated a packaged chocolate as "sugar free and 0g net carbs." The maths it used: 17g total carbs, minus 4g fibre, minus 13g sugar alcohol, equals 0g net. It collected more than 300 reactions. People bought it by the box.

The "zero net carbs" claim does not hold up, and for many people that chocolate raises blood sugar.

The net-carb subtraction is not a free pass

Net carbs were a marketing idea before they were a clinical one. The theory is that fibre and sugar alcohols are not fully absorbed, so you subtract them. Fibre, fair enough. Sugar alcohols are where it falls apart. The most common one in cheap "sugar-free" sweets is maltitol, and maltitol has a glycemic index around 35 — not zero. Subtracting all 13 grams as if they do nothing is simply wrong.

In our members' glucose data, "sugar-free" chocolates made with maltitol routinely produce a real rise of 20 to 40 mg/dL, just slower and lower than regular chocolate. "Less spike" is not "no spike."

The other half of the problem

Sugar alcohols that do pass through undigested ferment in the gut. In the quantities people eat when they believe something is "free," that means bloating, cramps, and diarrhoea. We have watched members eat half a bag because the label said zero, then feel awful and still see their glucose climb.

Which sweeteners actually behave

• Genuinely near-zero on glucose: erythritol, stevia, monk fruit, allulose. These are the ones worth using at home.
• Partial — counts more than the label says: maltitol, sorbitol, xylitol. Treat these as real carbs, roughly half.
• Not a free food either way: anything labelled "sugar-free" can still contain flour, milk solids, and fat that affect you.

How to read a "sugar-free" label honestly

1. Find the sugar alcohol on the ingredient list. If it is maltitol or sorbitol, count about half of those grams as carbs.
2. Ignore the "net carb" number on the front. Use total carbs and your own subtraction.
3. Watch the portion. "Sugar-free" makes people eat three times as much.
4. Test once with your meter or CGM. Your own number ends the argument.

The takeaway

"0g net carbs" is a claim, not a measurement. Sugar alcohols like maltitol raise glucose and upset your gut. If you want a chocolate fix that genuinely stays flat, make it from real food with a sweetener that behaves — we have one: sugar-free dark chocolate avocado mousse.