Buyers of Quest protein bars, cookies, candy and bake shop products may be covered by a proposed class action alleging Quest Nutrition sold them as healthy and made with “only quality ingredients” while they contain erythritol, a sweetener the complaint links to heart attack and stroke risk. No class has been certified and there is nothing to file yet.
Allegations Only · No Settlement Yet
This article describes a class action complaint. The statements below are unproven allegations. Quest Nutrition, LLC has not been found liable, there is no certified class, and nothing to claim at this time. This page is informational and is not legal advice.
What Is This About?
Quest Nutrition, LLC, the El Segundo, California maker of Quest protein bars and snacks, was sued in a proposed class action on September 23, 2026 in the U.S. District Court for the Central District of California. The case, Colby v. Quest Nutrition, LLC, Case No. 2:26-cv-10907, claims Quest markets its bars, cookies, candy and bake shop products as nutritious and made with “only quality ingredients” while leaving out that they are sweetened with erythritol.Erythritol is a sugar alcohol used in many low-sugar and “keto” foods. The complaint argues that recent medical research tying the sweetener to heart attack and stroke risk makes Quest’s health messaging misleading. Quest has not been found liable, and none of the allegations has been tested in court.
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What the Complaint Says Quest Promised
According to the complaint, Quest pitches its snacks to health-conscious shoppers with lines such as “only quality ingredients,” “athlete-worthy nutrition,” “big on protein, low on sugar and huge on flavor,” and “Quest Nutrition is on a mission to make the foods you crave work for you not against you.” The filing also points to how the products are sold: in the nutrition and sports-nutrition aisles of grocery and club stores, and at supplement retailers such as GNC and The Vitamin Shoppe, rather than next to candy.The complaint anticipates a defense built on the dessert-style flavor names. It argues that “Birthday Cake” or “Chocolate Brownie” describes the taste, not the nutrition, and that shoppers still read the product as a high-protein, low-sugar food made with good ingredients. It also cites the 2025 annual report of Quest’s parent company, The Simply Good Foods Company, which describes the brand as aimed at consumers seeking protein-rich foods that limit sugar.
Why Erythritol Is at the Center of the Case
The complaint relies on a line of research led by Dr. Stanley Hazen’s team at the Cleveland Clinic. A 2023 study in Nature Medicine of more than 4,000 people in the U.S. and Europe found that those with the highest blood erythritol levels had roughly twice the risk of a heart attack, stroke or death over three years. In the same paper, erythritol made platelets easier to activate in lab and animal tests, and a single erythritol-sweetened drink raised volunteers’ blood levels more than 1,000-fold, staying above the level tied to those platelet effects for at least two days. A 2024 follow-up in healthy volunteers found the same platelet effect with erythritol but not with glucose.The filing also cites a 2025 University of Colorado Boulder study in the Journal of Applied Physiology that exposed human brain blood-vessel cells to erythritol and reported changes linked to narrower vessels and weaker clot breakdown.
That research is contested, and the complaint itself describes the sweetener’s safety as the subject of “serious, credible, and unresolved scientific controversy.” The 2023 findings show an association, not proof that erythritol causes heart attacks or strokes. Erythritol remains a permitted food ingredient in the United States. The lawsuit does not have to prove the sweetener is dangerous in the way a personal injury case would. Its theory is that the risk is important enough that a brand advertising “quality ingredients” and health benefits should not stay silent about it.
Which Quest Products Are Named?
The complaint lists 45 products and says the class is not limited to them:- 28 protein bars, including the standard bars, the minis, the Overload bars and the Crispy Hero line
- Six cookies and four frosted cookies
- Four bake shop items: chocolate frosted donuts, chocolate brownies, blueberry muffins and chocolate chip muffins
- Three candy products: a peanutty caramel candy bar, peanut butter cups and chocolate-coated peanuts
What the Lawsuit Asks For
The case proposes a nationwide class of everyone in the U.S. who bought the products for personal use, plus a California subclass. It asserts claims under California’s Consumers Legal Remedies Act, Unfair Competition Law and False Advertising Law for the California subclass, with California’s Sherman food labeling law as a basis for the unfair-competition claim, and unjust enrichment for the nationwide class.The complaint seeks restitution of the alleged price premium, damages, and a court order requiring Quest to stop using the challenged statements and to add disclosures. Under the Consumers Legal Remedies Act, the plaintiff’s lawyers mailed Quest a notice letter the day the suit was filed. If Quest does not fix the practices within 30 days, the complaint says the plaintiff will amend to seek actual, punitive and statutory damages under that law.
A Separate Quest Case Over Lead in Protein Shakes
This suit is not the first recent case against Quest. A separate lawsuit filed in March 2026 in Los Angeles County Superior Court alleges some Quest ready-to-drink protein shakes carry lead above California’s Proposition 65 limit without a warning. That case is covered in our Quest protein shake lead lawsuit report. The two cases involve different products, different courts and different legal theories.The erythritol case also fits a broader wave of 2026 suits over sweeteners in “healthy” foods, most of them over allulose, such as the Magic Spoon protein cereal lawsuit.
What Happens Next?
As of September 30, 2026, the docket showed only the opening filings: the complaint, the summons request, the civil cover sheet and a notice of interested parties. Quest has not yet filed a response. Food labeling cases like this one usually move next to a motion to dismiss, where the company can argue that a reasonable shopper would not be misled or that federal food law preempts the claims.Nobody needs to do anything now. A class has not been certified, so there is no list of members and no form to fill out. Buyers who want to follow the case can keep receipts or order history for Quest bars and snacks, which could matter if the case settles later.
Read the Complaint
The full Colby v. Quest Nutrition, LLC complaint is embedded below:Colby v. Quest Nutrition, LLC — Class Action Complaint and Jury Demand (PDF, September 23, 2026)
Questions
Which Quest products does the lawsuit cover?
The complaint lists 45 products “including but not limited to” 28 Quest protein bar flavors (including the Crispy Hero and Overload lines), six cookies, four frosted cookies, four bake shop items (frosted donuts, brownies and two muffins) and three candy products. Quest protein shakes and chips are not on the list.
Is this the same case as the Quest protein shake lead lawsuit?
No. The earlier case, Barrales v. Quest Nutrition, is a California state-court Proposition 65 suit alleging some Quest ready-to-drink shakes contain lead without a warning. This case is a separate federal suit about erythritol in Quest bars, cookies, candy and bake shop products.
Has erythritol been banned or found to cause heart attacks?
No. Erythritol is still a permitted food ingredient in the United States. The complaint relies on studies from 2023 to 2025 that linked higher blood erythritol levels to cardiovascular events and to changes in platelet and blood-vessel function. The 2023 study found an association, which is not proof that erythritol causes heart attacks or strokes, and a court has not ruled on any of it.
Is this a personal injury case?
No. The suit is about money buyers allegedly overpaid because of the health and ingredient claims on the label. It does not seek compensation for heart attacks, strokes or other injuries.
Is there any money available now?
No. The case was just filed, no class has been certified and there is no settlement or claim form. If the case settles or a class is certified, buyers would be notified of any way to take part.
Sources
• Class Action Complaint — Colby v. Quest Nutrition, LLC, U.S. District Court for the Central District of California, Case No. 2:26-cv-10907 (filed September 23, 2026): Complaint (PDF)• Docket for Colby v. Quest Nutrition, LLC, No. 2:26-cv-10907 (C.D. Cal.), via CourtListener: CourtListener Docket
• Witkowski et al., “The artificial sweetener erythritol and cardiovascular event risk,” Nature Medicine (2023): PubMed
• National Institutes of Health — research summary on erythritol and cardiovascular events: NIH Research Matters
• Witkowski et al., erythritol and platelet reactivity in healthy volunteers, Arteriosclerosis, Thrombosis, and Vascular Biology (2024): PubMed
• Berry et al., erythritol and brain microvascular endothelial cell function, Journal of Applied Physiology (2025): Journal article
