According to a randomized clinical trial published in the journal Cell Metabolism, a very-low-carbohydrate ketogenic diet reduces liver fat and improves insulin sensitivity significantly more than Mediterranean or plant-forward diets when participants achieve a comparable 10% weight loss. Researchers found that dietary macronutrient composition independently alters metabolic responses, yielding a 67% reduction in hepatic triglycerides among ketogenic diet followers compared to roughly 45% for the other groups.
How Dietary Macronutrients Drive Liver Fat Reduction
Weight loss alone remains a primary prescription for metabolic disease, but a recent study from Cell Metabolism reveals that the specific balance of carbohydrates, fats, and protein changes the body’s response, particularly within the liver. According to the trial data, participants adhering to a very-low-carbohydrate ketogenic diet (KD) achieved a 67% reduction in hepatic triglyceride content, compared to an average 45% decrease for those following Mediterranean (MedDiet) and plant-forward (PF) diets.
The trial evaluated 55 individuals diagnosed with metabolically unhealthy obesity—defined as obesity accompanied by prediabetes and hepatic steatosis. Out of that initial group, 42 participants completed the five-month intervention. Researchers provided all study food and conducted weekly dietitian follow-ups, resulting in an adherence rate exceeding 95% across all groups.
"Dietary adherence, evaluated as the proportion of meals and snacks logged as consumed, exceeded 95% across groups."
Despite similar overall weight reductions of approximately 10% across cohorts, the metabolic pathways in the liver reacted differently to the absence of dietary carbohydrates.
Insulin Sensitivity and Prediabetes Remission Rates
Beyond lowering liver fat, the ketogenic diet produced starkly different outcomes regarding how skeletal muscle and the liver respond to insulin. According to the published findings, skeletal muscle insulin responsiveness increased by nearly 50% across all three diets. However, hepatic insulin sensitivity improved two to three times more among KD followers than among participants following the Mediterranean or plant-forward regimens.
The trial tracked multiple biomarkers to gauge systemic metabolic shifts. Prediabetes remission occurred in 50% of the participants in the ketogenic group, compared to 29% in the Mediterranean diet group and 7% in the plant-forward cohort. Furthermore, 24-hour plasma glucose exposure dropped by 20% in the KD group, contrasted with an approximate 8% reduction for the other diets.
Did you know? Fasting plasma insulin, mean very-low-density lipoprotein (M-VLDL) particle size, and the lipoprotein-insulin resistance (LP-IR) index showed the greatest reductions in participants following the very-low-carbohydrate ketogenic diet.
Fasting insulin levels and 24-hour plasma insulin exposure also dropped significantly more in the KD group, falling by 74%, compared to 44% for the Mediterranean diet and 27% for the plant-forward diet.
Oxidative Stress and Hormonal Shifts
The physiological differences extended to markers of inflammation, oxidative stress, and circulating hormones. Participants in the ketogenic diet group showed decreases in cystatin C, tumor necrosis factor-alpha (TNF-alpha), and plasminogen activator inhibitor-1 (PAI-1) concentrations, alongside an increase in estimated glomerular filtration rate (eGFR) values.
Urinary 8-isoprostane concentration, a recognized indicator of oxidative stress, declined exclusively among KD followers. At the same time, plasma glucagon concentrations rose by 52% in the ketogenic group while falling by 30% to 40% in the Mediterranean and plant-forward groups. The plasma glucagon-to-insulin ratio increased more than threefold among KD followers, remaining largely unchanged in the other cohorts.
Researchers noted that LDL cholesterol, apolipoprotein B, and 24-hour plasma triglycerides did not show statistically significant differences among the three diets. No serious adverse events were reported in any study group during the trial.
Frequently Asked Questions
What defines metabolically unhealthy obesity in this study? In this clinical trial, researchers defined metabolically unhealthy obesity as individuals presenting with obesity alongside prediabetes and hepatic steatosis, or excess liver fat.
Did all participants lose the same amount of weight? Yes. Participants across the ketogenic, Mediterranean, and plant-forward diet groups all achieved an average weight loss of approximately 10% of their initial body weight over the course of five months.
Which diet resulted in the greatest reduction of liver fat? Participants following the very-low-carbohydrate ketogenic diet experienced a 67% reduction in hepatic triglyceride content, compared to about 45% for those on the Mediterranean and plant-forward diets.
Did the study find changes in prediabetes remission rates? Prediabetes remission was observed in 50% of participants on the ketogenic diet, 29% of those on the Mediterranean diet, and 7% of those following the plant-forward diet.
Are these findings applicable to weight maintenance phases? The study’s authors caution that the trial could not determine whether similar hepatic benefits would occur if a ketogenic diet were introduced strictly during a weight maintenance phase rather than during active weight loss.