Keto Diet Achieves 67% Liver Fat Reduction Versus 45% in Mediterranean and Plant-Forward Arms in 42-Person RCT

Researchers at Washington University randomized 42 participants with obesity, prediabetes, and hepatic steatosis to 4-5 months of fully provisioned ketogenic (4% carb, 73% fat), Mediterranean (50% carb), or low-fat plant-forward (70% carb) diets. All groups lost equivalent weight and fat mass; insulin sensitivity improved across arms, yet the keto cohort showed greater reductions in liver fat (67% vs 45%), fasting insulin, and 24-hour glucagon elevation. Half of keto participants no longer met prediabetes criteria at exit, versus 29% and 7% in the other groups.

The controlled-feeding design eliminated adherence confounds common in free-living keto studies, yet the short duration and small sample limit extrapolation to long-term cardiovascular or renal outcomes. Prior observational data linking very-low-carb diets to LDL-C elevation were not replicated here, consistent with the authors’ note that weight loss itself may dominate lipid responses when fat quality is controlled.

Next steps require multi-center trials of at least 12 months that track hard endpoints such as biopsy-confirmed NASH regression and MACE incidence while monitoring lean mass and micronutrient status. Head-to-head comparisons with GLP-1 agonists in similar populations would clarify whether dietary composition adds benefit beyond caloric deficit.

Funding came from institutional sources without industry involvement in data analysis, though longer-term follow-up remains essential to assess durability.