A certified class of consumers who allege Kellogg Sales Co. overstates the heart-health benefits of sugary cereals won another victory when a federal court said two label statements don’t comply with federal regulations.

The ruling gives a boost to Stephen Hadley and others who allege the regulatory violations give rise to their claims under California’s Unfair Competition Law, which prohibits business conduct that’s unfair, unlawful, or fraudulent.

Consumers pursuing a similar suit against General Mills, however, saw their claims dismissed by a different judge in the Northern District of California.

At issue in the Kellogg’s case are a statement related...