View gallery Image Credit: Courtesy of Stephanie Buttermore/Instagram Stephanie Buttermore, the fitness influencer known for creating positive social media content on body positivity, died, her fiancé, Jeff Nippard, announced on March 6, 2026. She had just turned 36 two weeks beforehand. Naturally, heartbroken fans wondered what the cause of death was since Buttermore was known in the health and fitness space. "It is with profound sorrow that we share the sudden passing of Jeff's fiancée and partner of 10 years, Stephanie," an Instagram post shared to Nippard's account read.