Expert testimony found unreliable amidst claims of false advertising

Unreliable testimony by metrology and food safety expert excluded in class action for false and deceptive advertising

This case, Gwinn v. Laird Superfood, was decided in the United States District Court for the Southern District of New York on September 8, 2023. The Plaintiff, Lovelynn Gwinn, brought a class action lawsuit against the Defendant, Laird Superfood, charging Laird with false and deceptive advertising and labeling of its creamer and other food products in violation of New York General Business Law §§ 349 and 350 when Laird inaccurately described the serving sizes on the nutrition labels of its powdered creamer products. 

The Food, Drug, and Cosmetic Act (FDCA) and FDA regulations require nutrition labels to display the serving size as both a reference amount in grams and a common household measure. For powders, the reference amount is 2 grams. The household measure must be the one that most closely approximates 2 grams. Laird’s labels used teaspoon measurements. 

Gwinn claimed Laird violated the FDCA by using an inaccurate household teaspoon measurement on its labels. Gwinn relied on a metrology expert report by Nidal Kahl, a food safety expert and consultant, to show Laird’s measurements were wrong. Laird moved to exclude Kahl’s testimony. Without the expert testimony, Gwinn could not prove the labels were inaccurate.

Kahl tested one container of each of Laird’s seven powdered creamer products. Four products’ labels listed the serving size as 1 teaspoon. Three listed it as 3/4 teaspoon. Kahl emptied and weighed each container. Using a household teaspoon, he measured and weighed 12 samples from each product, calculating the average. He compared his measured weights to the label information.  

Kahl concluded that all the 1 teaspoon servings weighed over 2 grams, from 2.7 to 3.4 grams. The 3/4 teaspoons also exceeded 2 grams. When he divided the containers’ total weights by his measured teaspoon weights, he found fewer servings than the labels stated. 

In his work, Kahl presented two significant conclusions based on his research findings. First, he found that all containers with retail packaging listing 2g as a 1-teaspoon serving weight actually contained between 35% and 71% more product than indicated on the labels. This implies that consumers are unknowingly consuming significantly more of the product than they might believe based on the label. Second, Kahl’s data revealed a consistent product shortage in each retail container tested, ranging from 22% to 40%. This shortfall occurs because consumers end up using a larger product weight per serving, even when the label specifies 2g as the serving weight for 1 teaspoon.

Laird moved to exclude Kahl’s testimony as unreliable under Daubert and Federal Rule of Evidence 702. Laird argued Kahl’s consumer-perspective methodology was irrelevant to whether Laird followed labeling regulations. Laird also contended Kahl’s techniques were not scientifically reliable.

Metrology Expert Witness

Nidal Kahl completed his B.S. in Microbiology & Chemistry from Oregon State University. He is a food safety and food quality advisor and has been recognized in the food industry as a food safety expert and consultant. He has been serving the food industry at an international level for approximately 19 years in areas including regulatory compliance, process validation, routine microbiological analysis, and development and implementation of quality assurance programs. 

Currently, Nidal Kahl is the Director of Biogen Laboratory Developments, LLC. He is the Founder of Bolt Films, LLC; Kahl Properties, LLC; and Furniture Plus, LLC. He is also the Co-Founder of Celebrity Spa, LLC; Kahl & Company, LLC; and Celebrity Tan, LLC. 

Discussions by the Court

The Court began its discussion by setting forth the legal standard for admissibility of expert testimony. The Court stated that the admissibility of expert testimony is governed by Federal Rule of Evidence 702. Under Rule 702, expert opinion evidence is admissible if it will help the factfinder understand the evidence or determine a fact at issue, is based on sufficient data, and is the product of reliable principles reliably applied. The proponent of the evidence bears the burden of establishing its admissibility. Expert testimony must be both relevant and have a reliable foundation under Daubert.

The Court explained that Kahl’s testimony must show Laird violated FDA labeling rules to avoid preemption. The Court reiterated that claims challenging compliant labels are preempted. So Kahl’s testimony could only survive if it showed Laird used an incorrect household measure under the FDCA. At this stage, Gwinn had to submit evidence of a labeling violation. Kahl’s report failed to carry this burden.

The Court held Kahl’s testimony was not relevant. Kahl’s consumer-perspective measurements did not address whether Laird followed FDA’s rules for selecting serving sizes. Since Kahl did not purport to show Laird failed to comply with regulations, his testimony was irrelevant. Challenging compliant labels as misleading raised preemption issues beyond the scope of this lawsuit.

Additionally, the Court found Kahl’s methods were not reliably scientific under Daubert. Kahl described “a rudimentary measurement process” based on a consumer approach, not expert scientific techniques. He omitted critical details about his equipment, measurement process, and analytical practices. Kahl reported final values only to the nearest tenths place. While Kahl did not follow FDA Guidance, which recommended specific measurement standards, he also offered no academic support for his methodology or its error rate. This failed to demonstrate the intellectual rigor Rule 702 requires of expert testimony. Kahl’s generic description of “measuring” the products, without reliability controls, fell short of scientific standards.

The Court explained that Kahl’s failure to follow FDA guidance did not excuse his lack of reliable methodology. While Kahl did not have to adhere to the FDA guidance for manufacturers, Gwinn still had to show Kahl employed scientifically reliable principles and methods.

Kahl’s assessment of the products had significant limitations, including testing only one sample per flavor variety and not independently sourcing the products. His initial report lacked descriptions of product conditions, temperature information, and details about the experiment participants.

Had Kahl demonstrated relevance and baseline reliability, these flaws may not have required exclusion. But they provided additional reasons to find his opinions unreliable.

The Court rejected Gwinn’s arguments for admitting Kahl’s testimony. Gwinn argued mainly that Kahl did not have to follow the FDA guidance. But this missed the key point that Kahl still needed to demonstrate his methods were scientifically reliable, which he failed to do. Gwinn also contended Laird’s criticisms went to weight rather than admissibility. The Court disagreed, holding Kahl’s methodology lacked the validation required under Daubert and Rule 702.


In sum, the Court found Kahl’s testimony irrelevant and unreliable. His consumer-perspective testing shed no light on whether Laird followed labeling regulations. And his techniques plainly lacked scientific rigor. The relevance and reliability issues each independently required exclusion under Daubert and Rule 702. Without Kahl’s testimony, Gwinn could not show Laird’s labels were inaccurate under the FDCA. Since Kahl’s opinions were excluded, Gwinn had no evidence that Laird used an incorrect household serving size measure. As a result, Gwinn could not prove her underlying FDCA labeling violation claim.  This case awaits its final resolution.

Key Takeaways

This case demonstrates several important requirements for admitting expert testimony under Federal Rule of Evidence 702 and Daubert. First, experts must employ scientifically valid methodology. The Court excluded Kahl’s testimony because his basic consumer-perspective techniques lacked indicia of reliability like error controls and technical details. Second, reliability at every step matters. The Court stated that any unreliable step dooms the whole analysis. Kahl’s flaws like small samples and omitting product condition details highlighted this and the metrology expert’s testimony was subsequently found unreliable.  

Third, relevance is critical. The Court found Kahl’s testimony irrelevant because his consumer measurements did not address the key issue – whether Laird followed labeling rules. Even reliable methods yielding irrelevant opinions are inadmissible. Fourth, reliability requires intellectual rigor equaling field standards. Kahl’s generic descriptions fell below professional metrology standards. Fifth, Courts may consider additional factors bearing on reliability. Here, Kahl’s lack of peer-reviewed support further undermined reliability.

In summary, this case illustrates that expert testimony must be both methodologically reliable and relevant. Courts scrutinize each step of the analysis and whether the expert employed the expected level of intellectual rigor. Even minor shortcomings may render testimony inadmissible when fundamentally unreliable.