Low-sugar and keto protein bars cap added sugar at 2 grams or less and replace it with allulose, erythritol, monk fruit, soluble corn fibre, or a mix. They are aimed at people tracking carbs strictly, anyone on a ketogenic diet, and snackers who do not want a sugar crash an hour later. The category overlaps heavily with high-protein bars, but the defining filter here is sugar, not protein.

Quest is the anchor brand. The classic Quest Bar lineup typically sits at 1 g added sugar, 20 to 21 g protein, and 12 to 14 g fibre per bar. Price runs $1.60 to $2.00 per bar at Walmart and $1.80 to $2.30 per bar at Amazon, depending on flavour and pack size. No Cow and the keto-friendly versions of ONE Bar play in the same lane, usually $2.20 to $2.80 per bar. Atkins and Pure Protein round out the budget end, often under $1.60 per bar.

When you shop, scan for three things. First, total carbs minus fibre minus sugar alcohols (net carbs) should land at 3 to 6 g per bar for a true keto fit. Second, watch the soluble corn fibre and isomalto-oligosaccharide (IMO) content; some people get GI distress above 10 g per bar. Third, compare cost per gram of protein, not per bar, because a $2.20 Quest with 21 g often beats a $1.50 bar with 11 g. Our Value Score does that math for every bar listed here.

• Best all-rounder: Quest Chocolate Chip Cookie Dough (12-pack). 21 g protein, 1 g sugar, 14 g fibre, and the most consistent low-sugar texture on the shelf.
• Best for cravings: Quest S'mores. Same macros as the cookie-dough bar, but the marshmallow flavour is a useful swap when chocolate fatigue hits.
• Best lighter flavour: Quest Lemon Cake. The only non-chocolate, non-peanut entry in the Quest core lineup; helpful in summer.
• Best birthday-cake flavour: Quest Birthday Cake. Sprinkles, white-chocolate coating, still 1 g sugar.
• Best limited release: Quest Maple Glazed Donut. Worth trying once if you have hit flavour fatigue on the core line.