Metabolic and musculoskeletal implications of a ketogenic diet using animal and coconut saturated fat in rats

The ketogenic diet (KD) and coconut oil have been associated with weight loss benefits, but their effects on bone health remain unclear. This study aimed to evaluate the impact of a KD containing virgin coconut oil (VCO) on bone metabolism. Eight-week-old Wistar Hannover rats ( n = 8 per group) were assigned to four groups for 8 weeks: soy control (SC) with standard AIN-93 M diet, coconut control (CC) with VCO replacing soybean oil, KD with 81% animal fat, and KD-VCO with 40.5% animal fat + 40.5% VCO. Body composition was measured via dual-energy X-ray absorptiometry, while bone parameters were assessed using microcomputed tomography (µCT) and biomechanical testing. KD (40.86 ± 1.06%) and KD-VCO (39 ± 1.06%) groups showed higher fat mass percentages only in comparison to SC (31.66 ± 1.06%); p < 0.05. Lean mass was lower in KD (191 ± 4.64 g) than in SC (245 ± 4.64 g), and lean mass percentage was reduced in both KD (57.75 ± 2.08%) and KD-VCO (59.37 ± 2.08%) compared to SC (66.75 ± 2.08%); p < 0.05. µCT revealed cortical microstructure deterioration in both KD groups. Biomechanical testing showed decreased bone strength in KD groups: SC= (68.23 ± 2.06 N), KD (51.54 ± 2.20 N), and KD-VCO (59.26 ± 2.20 N); p < 0.05. In conclusion, the inclusion of coconut oil in a KD did not prevent the adverse effects on body composition and bone strength.