A controlled clinical trial from Washington University indicates that a very low-carbohydrate ketogenic diet may significantly improve liver fat and blood sugar control in people with obesity-related metabolic conditions, surpassing other dietary plans.
A tightly controlled clinical trial from Washington University School of Medicine in St. Louis suggests that a very low-carbohydrate ketogenic diet may do more than help with weight loss in people with obesity, prediabetes and fatty liver disease. The study found that while three markedly different diets led to broadly similar weight loss and general metabolic gains, the ketogenic plan produced the strongest improvements in liver fat and blood sugar control.
The research, published in Cell Metabolism, followed 55 adults who were randomly assigned to one of three eating plans for about five months: a ketogenic diet, a high-carbohydrate low-fat plant-forward diet or a Mediterranean-style diet. All participants were given food by the researchers and met weekly with a dietitian, making the trial far more controlled than most real-world diet studies. According to the researchers, each group lost about 10% of starting body weight and improved muscle insulin sensitivity by roughly 50%, suggesting that weight loss itself was the main driver of better insulin response in muscle.
The liver results were more distinctive. Participants on the ketogenic diet saw liver insulin sensitivity improve by two to three times more than those in the other groups, while liver fat fell by 67%, compared with 45% in the Mediterranean and plant-forward groups. Average 24-hour blood sugar levels dropped 20% in the ketogenic group, versus 8% in each of the other diets, and daily insulin levels fell more sharply as well. Half of the people on the ketogenic plan no longer met the definition of prediabetes by the end of the trial, compared with 29% in the Mediterranean group and 7% in the high-carbohydrate group.
The findings fit with earlier research, but they also sharpen the debate over how much carbohydrate restriction matters for fatty liver disease. A 2007 pilot study and later reviews of the evidence suggested low-carbohydrate diets could reduce liver fat, although the overall data were mixed and often limited by small sample sizes. More recent work, including a 2021 randomised trial, has also found that carbohydrate-restricted diets can improve liver steatosis. Still, Washington University’s study was small, lasted only about five months and supplied all meals, so the authors caution that its results may be hard to reproduce in everyday life.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
