A new randomized clinical trial suggests that the type of diet a person follows may matter as much as the number on the scale, with liver outcomes differing even when weight loss is similar across groups. The findings, published in Cell Metabolism and reported by News Medical on August 31, 2026, add to growing evidence that macronutrient balance can influence cardiometabolic health beyond weight reduction alone.
Three diets, similar weight loss, different liver responses
In the study, researchers compared a very-low-carbohydrate ketogenic diet, a Mediterranean diet and a fat-restricted plant-forward diet in adults with metabolically unhealthy obesity. All participants lost roughly 10% of body weight after about five months, but the ketogenic group showed greater reductions in liver fat than the other two groups.
The report says the trial involved 55 people who were randomized to one of the three diets, with 42 completing the study and being included in the final analysis. The participants were provided with all study food and had weekly dietitian follow-ups to support adherence.
Alongside body composition, the team assessed hepatic lipogenesis, oral glucose tolerance, pancreatic beta-cell function and blood pressure. Blood tests were also used to measure lipids, triglycerides, glucose, cytokines and hormones including insulin, glucagon and C-peptide.
Why the liver findings matter
According to the report, the results may be particularly relevant for people with obesity alongside prediabetes and hepatic steatosis, a group at higher risk of metabolic disease. The study adds to the idea that the composition of a diet may alter metabolic health independently of weight loss itself.
The researchers noted that previous diet studies have sometimes been limited by poor adherence or unequal weight loss between groups, making it difficult to separate the effects of diet composition from the effects of weight loss. In this trial, the closer matching of weight loss helps strengthen the case that macronutrient balance may have its own metabolic impact.
The report says the study findings suggest a very-low-carbohydrate ketogenic diet, when paired with about 10% weight loss, may produce greater improvements in some cardiometabolic measures among people similar to those studied. It also notes that larger studies will be needed to determine whether these changes translate into lower long-term disease risk.
For clinicians and patients, the takeaway is not that one diet will suit everyone, but that the liver may respond differently depending on how carbohydrates, fats and protein are distributed in the eating plan. That distinction could shape future diet planning and nutrition research, especially in people with metabolic dysfunction.
The original report can be found at News Medical, while the trial was published in Cell Metabolism.
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