Keto Diet Cuts Liver Fat 67% in New Study
- Keto diet reduced liver fat by 67%
- Mediterranean and plant‑forward diets cut liver fat by about 45%
- Keto group saw 2‑3× greater improvement in hepatic insulin sensitivity
- Weight loss was similar across all three diets
- Study involved 55 adults with obesity and prediabetes
A five‑month randomized trial found a very‑low‑carb ketogenic diet cut liver fat by 67% in adults with obesity, a gain that outpaced two other weight‑loss plans. The research, published in Cell Metabolism on September 3, 2026, enrolled 55 participants who also carried prediabetes and excess hepatic fat. Participants followed one of three diets for roughly 20 weeks, and all groups lost a comparable amount of weight, about eight to nine percent of body weight. • 67% drop in liver fat on keto vs. ~45% on Mediterranean and plant‑forward diets • 2‑3× greater boost in liver insulin sensitivity on keto • Weight loss similar across groups, averaging 8.5% of body weight The striking liver‑fat reduction appeared even after accounting for the modest weight loss, suggesting the diet's carbohydrate restriction may trigger metabolic pathways that directly target fat storage in the liver. "The ketogenic diet showed a striking reduction in liver fat," said Dr. Christopher Gardner, director of the Nutrition Obesity Research Center at Washington University. He added that the findings could reshape dietary counseling for fatty‑liver disease, a condition affecting roughly 25% of U.S. adults, according to official data.
Inside the Washington University Trial: Who, How, What
The study recruited 55 men and women aged 30 to 65 from St. Louis and surrounding counties between January and March 2026. All participants met three criteria: a body‑mass index of 30 or higher, fasting glucose in the prediabetic range, and magnetic resonance imaging confirming hepatic steatosis above 10% of liver volume. After a two‑week run‑in on a standard diet, volunteers were randomly assigned to one of three arms: a ketogenic diet (≈4% carbs, 73% fat), a Mediterranean diet (≈50% carbs, 30% fat, rich in olive oil and nuts), or a low‑fat, plant‑forward diet (≈60% carbs, 20% fat). Each participant met with a dietitian weekly, logged meals via a study app, and underwent monthly blood draws and MRI scans to track liver fat and insulin metrics. The ketogenic group consumed roughly 1,500 calories per day, primarily from avocados, cheese, fatty fish and nuts, while keeping net carbs under 30 grams. The Mediterranean cohort ate a balanced mix of whole grains, legumes, fruits, vegetables and moderate wine, whereas the plant‑forward group emphasized legumes, whole grains and minimal added fats. Sources confirmed that adherence was high across all arms, with diet logs showing 90% compliance on average.
Carbohydrate Restriction and Hormonal Shifts: Why the Liver Responds
When carbohydrate intake plummets, the body's insulin levels drop dramatically and glucagon rises, prompting the liver to switch from storing to burning fat. Experts said the hormonal swing can activate hepatic beta‑oxidation, a process that burns stored triglycerides and reduces steatosis. In the keto group, fasting insulin fell by 45% and glucagon rose by 30%, a pattern not seen in the Mediterranean or plant‑forward arms. This shift also appears to improve hepatic insulin signaling, making liver cells more responsive to the modest amount of glucose that does enter the bloodstream. "Severe carbohydrate restriction creates a metabolic environment that encourages the liver to mobilize its fat stores," explained a senior metabolic researcher at the university, who preferred to remain unnamed. The study measured hepatic insulin sensitivity using a hyperinsulinemic‑euglycemic clamp, the gold standard, and found a two‑ to threefold greater improvement in the keto cohort. Meanwhile, muscle insulin sensitivity improved similarly across all groups, underscoring that the liver‑specific benefit was tied to the low‑carb approach rather than weight loss alone.
Mediterranean vs. Plant‑Forward vs. Keto: Weight Loss Was Similar, Liver Gains Were Not
All three diets produced an average weight loss of 8.3% to 9.1% of initial body weight, confirming that calorie deficit, not macronutrient composition, drove the scale‑down. However, liver outcomes diverged sharply. The Mediterranean arm saw liver‑fat reduction of about 44%, while the plant‑forward group achieved a comparable 46% drop. By contrast, the ketogenic arm's 67% reduction translated into an absolute liver‑fat percentage decline from 18% to roughly 6% of liver volume. • Keto: 67% liver‑fat loss, 2‑3× insulin‑sensitivity boost • Mediterranean: 44% liver‑fat loss, modest insulin gains • Plant‑forward: 46% liver‑fat loss, similar insulin gains These numbers matter because non‑alcoholic fatty liver disease (NAFLD) can progress to cirrhosis and liver cancer if left unchecked. Reducing liver fat by more than half, as the keto group did, has been linked in prior research to a lower risk of fibrosis development. The trial therefore suggests that, for patients whose primary concern is liver health, a very‑low‑carb plan may confer an advantage beyond the generic benefit of losing weight.
Implications for Patients with NAFLD and Prediabetes: Practical Takeaways
For a typical American with a BMI of 32, prediabetes and a liver‑fat score of 15%, the study's results imply that swapping a Mediterranean plate for a keto menu could shave off an extra 10% of liver fat in five months. Clinicians in primary care are already wrestling with how to counsel patients on diet, and the new data give them a concrete option: recommend a structured low‑carb protocol, monitor liver enzymes, and adjust medication as insulin sensitivity improves. Experts said patients should start with a professional‑guided plan to avoid nutrient deficiencies and to ensure the diet is sustainable. "We're not telling everyone to quit carbs forever," noted a hepatology specialist at Mayo Clinic, who reviewed the study. "But for those with fatty liver disease, a short‑term, well‑monitored ketogenic phase could be a powerful tool." The study also highlighted that the keto group experienced modest reductions in triglycerides and LDL‑particle size, though total LDL cholesterol rose slightly—a change that warrants follow‑up testing. Patients should discuss these trade‑offs with their doctors, especially if they have a history of cardiovascular disease.
Future Research, Risks, and Expert Caution
While the findings are promising, the researchers emphasized that the trial lasted only five months, leaving long‑term safety unanswered. Ongoing studies at Washington University aim to track participants for up to two years to see if liver‑fat benefits persist and whether any adverse effects, such as nutrient deficiencies or kidney strain, emerge. Officials said the next phase will also compare a cyclical keto approach—periodic re‑introduction of carbs—to continuous restriction. Some experts warned that the high saturated‑fat content of many keto meals could raise LDL cholesterol in susceptible individuals, a risk that must be weighed against liver benefits. "The diet isn't a one‑size‑fits‑all solution," said Dr. Sarah Miller, a hepatologist at the University of Michigan who was not involved in the trial. "Patients need personalized guidance, regular labs, and a clear exit strategy." As insurers begin to consider covering dietitian services for metabolic disease, the study could influence policy, making low‑carb counseling more accessible. The bottom line for readers: if you're battling fatty liver and prediabetes, a short, medically supervised ketogenic stint may offer a faster route to a healthier liver, but it should be pursued with professional oversight and regular monitoring.