We evaluated the effects of a 12-week hypocaloric ketogenic diet (KD) on glucose and lipid metabolism, as well as body mass, in overweight, obese, and healthy-weight females. One hundred adult females completed the study, including 64 obese (97.99±11.48kg), 23 overweight (75.50±5.12 kg), and 11 with optimal body mass (65.93±3.40 kg). All participants followed a KD consisting of less than 30 g of carbohydrates, approximately 60 g of protein, and 140 g of fat per day (80% unsaturated and 20% saturated fat).Methods: Glucose (Gl), insulin (I), glycated haemoglobin (HbA1c), HOMA-IR, triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) were measured before and after the intervention. Additionally, body mass (BM), waist circumference (WC), hip circumference (HC), and thigh circumference (TC) were recorded. Results: After 12 weeks of the KD, significant improvements were observed in most biochemical variables across all groups. BM, TC, WC, and HC were significantly reduced in all participants. Notably, obese participants showed greater reductions in all variables compared to overweight and healthy-weight females. Conclusion: A 12-week KD led to more pronounced improvements in biochemical markers and body mass in obese females compared to other groups. A KD may be particularly beneficial for obese females with hyperglycaemia, hyperinsulinemia, and lipid profile disturbances.