Allulose

One US cup of allulose weighs 192 grams. Going the other way, 100 grams is about 0.52 cups.

Also called allulose, D-allulose, D-psicose, psicose, granulated allulose, rare sugar.

One cup of granulated allulose weighs about 192 grams (0.812 g/mL) — slightly less than granulated sugar (198-200 g/cup) but in the same physical density band. Multiple producer labels (Anthony's Goods, RxSugar, Wholesome Sweeteners) converge at 4 grams per teaspoon. A commonly-cited alternative figure of 160 g/cup from CupsToGrams and similar aggregator sites is a significant outlier and appears wrong — it does not match producer labels, published physical characteristics of the crystal, or independent references from Levels and Keto-Mojo.

Allulose (D-allulose, D-psicose) is a monosaccharide with molecular formula C6H12O6 and molecular weight 180.16 g/mol — the same formula as fructose but a C-3 epimer, meaning the two molecules are identical except for the stereochemistry at one carbon. It is about 70% as sweet as sucrose, provides only 0.4 kcal/g (compared to 4 kcal/g for sucrose), and is not metabolized by the body: about 70% is absorbed in the small intestine and excreted unchanged in urine within 24 hours. The FDA classified allulose as GRAS in 2019 and issued a labeling exemption allowing food manufacturers to exclude allulose from Total Sugars and Added Sugars on the Nutrition Facts panel — the only sugar to receive this treatment. Commercial allulose is produced by enzymatic conversion of fructose (typically from non-GMO corn) using D-tagatose 3-epimerases or D-allulose 3-epimerases.

Granulated allulose crystallizes as a white anhydrous crystalline solid with a melting point around 108-109°C and appearance essentially indistinguishable from table sugar. Bulk density of the granulated form is slightly less than sucrose (~0.812 g/mL vs ~0.845 for granulated sucrose). Producer nutrition labels for Anthony's Goods Allulose Sweetener and RxSugar Allulose Sugar both anchor at 4 g per teaspoon — 4 g / 4.929 mL = 0.8115 g/mL, reading out to 192 g per US customary cup (236.588 mL). Wholesome Sweeteners lists a 5-gram serving without stating the volume; the figure is consistent with a 1.25-teaspoon serving at the same 4-g/tsp convention. Levels and Keto-Mojo both cite 4 g per teaspoon and 12 g per tablespoon in their reference materials. The 4-g/tsp figure matches the FDA reference amount customarily consumed for sugars, which is a labeling convention — but it is also physically accurate for allulose because the crystal bulk density is close to sucrose's.

King Arthur Baking's Ingredient Weight Chart does not list pure allulose. It does list a King Arthur "Baking Sugar Alternative" at 1 cup = 6 oz = 170 g, which is often confused with pure allulose but is actually a proprietary erythritol-based blend. The KA product's ingredient list, in order, is erythritol, soluble corn fiber, allulose, cane sugar-derived fructan fiber, monk fruit extract, stevia leaf extract, and natural flavor — erythritol is the primary component, allulose the third. The 170 g/cup figure applies to that specific blend, not to pure allulose. Bakers substituting pure allulose for the KA blend by volume will get about 13% more mass (192 vs 170 g/cup) and different browning behavior, because pure allulose Maillard-browns more aggressively than erythritol.

For practical baking, replace granulated sugar by weight or by volume depending on the goal. For sweetness parity, use about 1.3 cups of allulose per 1 cup of granulated sugar (accounting for allulose's 70% relative sweetness). For structural parity (creaming with butter, providing bulk in cakes and cookies), a 1-to-1 substitution by volume works reasonably: the 4% mass difference per cup (192 vs 200) is under the sugar-category tolerance. Reduce the oven temperature by about 25°F (15°C) and check for doneness at ~75% of the recipe time, because allulose participates in Maillard browning more aggressively than sucrose and finished goods will over-color at unadjusted temperatures. Allulose resists recrystallization in high-moisture applications, which makes it excellent for smooth frostings, ice cream that stays scoopable directly from the freezer, and no-crystallize syrups.

The FDA-accepted maximum tolerable daily intake is about 33-36 grams per day for a 60 kg adult — roughly 8 teaspoons or 2 tablespoons per day, above which some people experience GI discomfort (bloating, mild osmotic diarrhea) similar to but less pronounced than with sugar alcohols. This is a practical usage limit rather than a safety concern.