Dunkin’ sells its Dunkin’ Zero energy drinks as having “0g of sugar.” A proposed class action filed in federal court in Boston says each medium drink contains roughly 9 grams of a sugar, and each large about 11 to 13 grams.
The ingredient is allulose, a low-calorie sweetener. Whether allulose counts as “sugar” under federal labeling rules sounds like a technicality. It is the entire case, and a federal appeals court answered the question this summer in a way that does not help Dunkin’. Here is what the complaint says, the rule it relies on, and what could happen next. These are allegations, and Dunkin’ has not yet responded in court.
The lawsuit
Wells v. Dunkin’ Brands, Inc., No. 1:26-cv-14463, was filed September 30, 2026 in the U.S. District Court for the District of Massachusetts against Dunkin’ Brands, which is headquartered in Canton, and its parent, Inspire Brands. According to the complaint:
- The plaintiff, Phyllis C. Wells of Chicago, says she bought Dunkin’ Zero drinks two to three times a week at a Chicago drive-through because she was trying to limit sugar, and relied on the “zero sugar” claims.
- The drinks are sold as “zero sugar” and “0g of sugar.” The complaint covers every Dunkin’ Zero flavor introduced since March 4, 2026, in all sizes.
- Dunkin’s own Allergen and Ingredient Guide lists allulose in the flavored syrups, the complaint says. It alleges allulose is the main ingredient in the syrups and the only one contributing carbohydrates.
- The complaint seeks to represent everyone in the U.S. who bought the drinks since March 4, 2026, plus an Illinois subclass. It claims violation of the Illinois consumer fraud law, breach of express warranty under the Massachusetts Uniform Commercial Code, negligent misrepresentation and unjust enrichment.
- It asks for damages, restitution, attorney’s fees, and an order requiring Dunkin’ to stop the “zero sugar” marketing or add corrective disclosures.
Boston 25 News said it reached out to Dunkin’ for comment.
The rule: “zero sugar” means less than half a gram
“Zero sugar” is not marketing language the FDA leaves open. Under 21 C.F.R. § 101.60(c)(1), a food may not use terms like “sugar free,” “no sugar” or “zero sugar” unless, among other things:
- it “contains less than 0.5 g of sugars, as defined in § 101.9(c)(6)(ii),” per serving; and
- it “contains no ingredient that is a sugar or that is generally understood by consumers to contain sugars” unless the ingredient list flags it with an asterisk saying it “adds a trivial amount of sugar” or similar.
The regulation explains why: consumers “may reasonably be expected to regard terms that represent that the food contains no sugars or sweeteners e.g., ‘sugar free,’ or ‘no sugar,’ as indicating a product which is low in calories or significantly reduced in calories.”
The definition it points to, § 101.9(c)(6)(ii), defines total sugars as “the sum of all free mono- and disaccharides (such as glucose, fructose, lactose, and sucrose).”
Is allulose a sugar? The Chobani case
Allulose is a monosaccharide, a single-unit sugar molecule chemically related to fructose. An industry description quoted in the complaint says it is “absorbed by the body, but not metabolized, so it is nearly calorie-free.” In guidance, the FDA said it would use enforcement discretion and allow companies to leave allulose out of the “Total Sugars” and “Added Sugars” lines on Nutrition Facts labels while it considered changing its rules.
On July 27, 2026, the U.S. Court of Appeals for the Seventh Circuit held that this guidance does not change what the regulation says. In Franco v. Chobani, LLC, No. 25-2087, consumers sued over Chobani’s “zero sugar” yogurt, which had four grams of allulose per serving. A district court had thrown the case out, deferring to the FDA guidance. The Seventh Circuit reversed:
“There’s no dispute that allulose is a monosaccharide. Because the definition includes every monosaccharide and the following parenthetical is merely a list of examples, allulose is a sugar under § 101.9(c)(6)(ii).”
The court called the allulose guidance “an announcement of a change in enforcement policy,” not an interpretation of the rule. And it noted that the FDA itself, in an amicus brief in that appeal, took the position that the regulation is unambiguous and that total sugars include all monosaccharides, including allulose.
The Dunkin’ complaint quotes Franco repeatedly. The Seventh Circuit’s decision does not bind the federal court in Massachusetts, which sits in the First Circuit, but it is the most recent appellate ruling on the question and the FDA’s own position in it points the same way.
Why the regulation matters for a state-law lawsuit
Federal food labeling law generally preempts state laws that impose labeling requirements different from the federal ones. Consumers can sue under state law only for violating requirements identical to the federal standards. That is why Franco turned on whether allulose is a sugar under the federal regulation: if it is, a “zero sugar” claim on a product containing grams of it violates the federal standard, and a state-law claim mirroring that standard can go forward.
Even then, the plaintiffs still have to prove consumers were actually misled. The Seventh Circuit said how reasonable consumers understand sugar claims is a question of fact, to be decided after discovery.
The Massachusetts angle: a 93A claim is coming
A footnote in the complaint says the plaintiff intends to add a claim under the Massachusetts Consumer Protection Act, G.L. c. 93A, “upon the expiration of the presuit notice period.” That refers to § 9(3) of the statute, which requires a written demand for relief to be sent to the business at least 30 days before a 93A lawsuit is filed. If the business makes a written settlement offer within 30 days and the claimant rejects it, the business can later use that offer to cap its liability if a court finds the offer was reasonable.
Chapter 93A claims can carry double or triple damages for willful or knowing violations, which is why consumer class actions against Massachusetts companies often add them.
What this means if you drink Dunkin’ Zero
- Nothing to file yet. This is a proposed class action. No class has been certified and there is no settlement or claim form. Be wary of anyone asking you to submit personal information for a “Dunkin’ settlement.”
- Allulose is not the same as table sugar for most purposes. The lawsuit is about whether the label is accurate and legal, not about whether allulose is unhealthy. Anyone limiting sugar for medical reasons should ask their doctor how allulose fits.
- Keep receipts or app records if you buy the drinks regularly. If a class is certified or a settlement reached, proof of purchase can matter.
Frequently asked questions
What is the Dunkin’ Zero lawsuit about?
A proposed class action filed September 30, 2026 in federal court in Boston alleges Dunkin’ Zero drinks are marketed as “zero sugar” and “0g of sugar” but contain about 9 grams of allulose in a medium and 11 to 13 grams in a large. It argues allulose is a sugar under FDA rules. The claims are allegations.
Is allulose a sugar?
Chemically it is a monosaccharide. The Seventh Circuit held in Franco v. Chobani (July 27, 2026) that it is a sugar under the FDA’s definition in 21 C.F.R. 101.9(c)(6)(ii), even though FDA guidance lets companies exclude it from the sugar lines on Nutrition Facts labels.
What does “zero sugar” legally mean?
Under 21 C.F.R. 101.60(c)(1), less than 0.5 grams of sugars per serving and no sugar ingredient unless flagged as adding only a trivial amount.
Can I join the Dunkin’ class action?
Not yet. No class has been certified. If one is, or if there is a settlement, notice will be given to class members.
Sources: Complaint, Wells v. Dunkin’ Brands, Inc., No. 1:26-cv-14463 (D. Mass. filed Sept. 30, 2026), read in full via CourtListener’s RECAP archive; Boston 25 News, October 7, 2026. Franco v. Chobani, LLC, No. 25-2087 (7th Cir. July 27, 2026), read on CourtListener. 21 C.F.R. 101.60(c)(1) read at ecfr.gov. G.L. c. 93A, section 9 read at malegislature.gov. All claims against Dunkin’ and Inspire Brands are allegations that have not been proven. General information about the law, not legal advice.