Introduction
Ketogenic diets, characterized by very low carbohydrate intake and increased fat consumption, have gained significant attention as a potential therapeutic strategy in metabolic dysfunction-associated steatotic liver disease. The rationale is biologically appealing: by reducing insulin levels and promoting lipolysis and hepatic β-oxidation, ketogenic diets may rapidly decrease intrahepatic fat and improve metabolic parameters. In an era where lifestyle interventions remain the cornerstone of MASLD management, understanding whether dietary composition—beyond simple caloric restriction—can meaningfully influence liver fat is of major clinical importance.
Summary
This article critically evaluates a recent mechanistic study suggesting superior reductions in intrahepatic triglyceride content and insulin resistance with ketogenic diets compared to non-ketogenic diets. While the findings support a “starvation-like” metabolic shift with increased fat oxidation and reduced insulin levels, the authors highlight key methodological limitations that challenge causal interpretation. The most important concern is the non-randomized crossover design, where all participants received the ketogenic diet first, followed by the non-ketogenic diet after a prolonged interval, introducing significant time-related confounding. Additionally, a substantial imbalance in protein intake between the two diets raises the possibility that observed metabolic changes may be driven by increased protein rather than ketosis itself. Finally, reliance on HOMA-IR as a surrogate for hepatic insulin sensitivity is questioned, as reductions in insulin and glucose during low-carbohydrate intake may reflect decreased metabolic demand rather than true improvement in insulin signaling. Overall, while ketogenic diets show potential in reducing liver fat, these findings underscore the need for rigorously designed trials before attributing benefits specifically to carbohydrate restriction.