We investigated the effects different diets on adipose tissue, liver and serum morphology and biomarkers in rats that voluntarily exercised. Male Sprague-Dawley rats (~9-10 weeks of age) exercised with resistance-loaded voluntary running wheels (EX; wheels loaded with 20-60% body mass) or remained sedentary (SED) over 6 weeks. EX and SED rats were provided isocaloric amounts of either a ketogenic diet (KD; 20.2%-10.3%-69.5% protein-carbohydrate-fat), a Western diet (WD; 15.2%-42.7-42.0%), or standard chow (SC; 24.0%-58.0%-18.0%); n=8-10 in each diet for SED and EX rats. Following the intervention, body mass and feed efficiency was lowest in KD rats independent of exercise (p<0.05). Absolute and relative (body mass-adjusted) omental adipose tissue (OMAT) masses were greatest in WD rats (p<0.05) and OMAT adipocyte diameters were lowest in KD-fed rats (p<0.05). None of the assayed OMAT or subcutaneous (SQ) protein markers were affected by the diets [total acetyl coA carboxylase (ACC), CD36 and CEBPα or phosphorylated NF-B/p65, AMPKα and hormone-sensitive lipase (HSL)], although EX unexpectedly altered some OMAT markers (i.e., higher ACC and phosphorylated NF-B/p65, and lower phosphorylated AMPKα and phosphorylated HSL). Liver triglycerides were greatest in WD rats (p<0.05) and liver phosphorylated NF-B/p65 was lowest in KD rats (p<0.05). Serum insulin, glucose, triglycerides and total cholesterol were greater in WD and/or SC rats compared to KD rats (p<0.05), and serum β-hydroxybutyrate was greater in KD versus SC rats (p<0.05). In conclusion, KD rats presented a healthier metabolic profile, albeit the employed exercise protocol minimally impacts any potentiating effects that KD has on fat loss.