The study assessed the effectiveness of the Fitterfly diabetes program in managing lean diabetes (BMI <23 kg/m²) over 90 days. Deidentified data of 126 participants showed significant improvements in HbA1c levels, weight, BMI, and waist-to-hip ratio among participants. Higher baseline HbA1c levels correlated with greater reductions post-program. A notable percentage achieved recommended HbA1c values (≤7%), highlighting improved glycaemic control. The findings emphasize the importance of lifestyle interventions, including personalized diet plans and remote coaching, in managing diabetes regardless of BMI.