Personalized Combination of a Ketogenic Diet and Low-Dose Semaglutide for Cardiometabolic Health: A Retrospective Case Series

Background/Objectives: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), particularly semaglutide, have demonstrated efficacy for weight loss in obesity; however, up to 40% of weight lost may derive from lean body mass. The ketogenic diet independently improves insulin sensitivity and promotes fat oxidation while preserving lean tissue. This study aimed to describe changes in body composition, insulin sensitivity, and cardiometabolic markers in patients who followed a personalized ketogenic dietary protocol while receiving low-dose semaglutide over a 6-month insulin resistance reversal program. Methods: Seven analyzed adults (six female, one male) with overweight or obesity (baseline BMI 25.6–47.2 kg/m2) participated in a clinician-supervised 6-month program combining a whole-food ketogenic diet with semaglutide (≤1.0 mg/week). Body composition and fasting metabolic markers were assessed at 1, 3, and 6 months. Results: Mean total weight loss was 21.9 kg, of which a mean of 92% was attributable to BIA-estimated fat mass. Skeletal muscle mass was largely preserved as measured by BIA (mean loss 1.2 kg), and one patient gained lean tissue. Fasting insulin declined by a mean of 15.6 µIU/mL. Visceral fat decreased by a mean of 37.0%. Six of seven patients showed reductions in high-sensitivity C-reactive protein. Triglycerides decreased in six of seven patients, and HDL cholesterol increased in all seven. LDL cholesterol responses were heterogeneous. Conclusions: In this small, uncontrolled case series, combining a ketogenic diet with low-dose semaglutide was associated with substantial fat loss, apparent preservation of lean mass as measured by BIA, and improvements in insulin sensitivity and cardiometabolic markers. Because the semaglutide dose and dietary protocol were individualized to each patient’s response, the program illustrates a personalized approach to insulin resistance. These preliminary findings are hypothesis-generating and warrant confirmation in controlled prospective studies.