Over the 6-week period, KD rats consumed 3,540 ± 74 (mean±SD) total kcal, WD rats consumed 3,638 ± 83 total kcal, and StdChow rats consumed 3,025 ± 145 total kcal (WD>KD>StdChow; p < 0.001). Remarkably, however, 6-week feed efficiency (g bodyweight gained/kcal consumed) was greater in the WD and (0.042 ± 0.007g/kcal) StdChow (0.045 ± 0.012g/kcal) compared to the KD rats (0.018 ± 0.006g/kcal) (p < 0.001). Total body mass at sacrifice was also significantly less in KD compared to WD and StdChow groups (397 ± 26,494 ± 36 and 472 ± 49g, respectively; p < 0.001). KD and StdChow had significantly less absolute and relative omental (absolute omental: 0.8 ± 0.3g and 1.2 ± 0.4g vs 1.6 ± 0.6g, respectively, p < 0.05; relative omental: 2.1 ± 0.7 and 2.4 ± 0.7 vs 3.2 ± 1.2g/kg, respectively, p < 0.05) compared to WD rats. KD and StdChow also had significantly less perirenal adipose tissue compared to WD (absolute perirenal: 4.2 ± 1.3 and 5.4 ± 1.4 vs 7.8 ± 1.8g, respectively, p < 0.05; relative perirenal: 10.6 ± 2.8 and 11.4 ± 2.4 vs 15.6 ± 3.0g/kg, respectively, p < 0.05). KD had significantly less absolute inguinal subcutaneous (SQ) and scapular brown fat than WD (absolute SQ: 4.3 ± 1.5 vs 6.6 ± 2.4g/kg; absolute brown fat: 0.6 ± 0.2 vs 0.8 ± 0.3g) but similar relative SQ and brown fat weights. Serum triglyceride levels were greater in WD (319.7 ± 109.8mg/dL) versus StdChow rats (163.0 ± 67.0mg/dL; p < 0.05), and both groups presented greater levels versus KD rats (69.9 ± 21.2mg/dL; p < 0.05). Serum cholesterol and glucose levels were significantly less in the KD compared to WD and StdChow rats (cholesterol: 67.7 ± 6.8 vs 89.9 ± 10.8 and 87.0 ± 16.9mg/dL, respectively, p < 0.05; glucose: 166.1 ± 49.6 vs 278.3 ± 99.9 and 256.6 ± 86.9mg/dL, respectively, p < 0.05). White blood cell counts were greater in the WD compared to KD and StdChow groups (15.3 ± 2.6 vs 7.9 ± 2.8 and 9.5 ± 4.3 x103 cells/µL, p < 0.05), and white blood cell differentials between groups are discussed herein.