A tightly controlled clinical trial suggests that a ketogenic diet may deliver greater improvements in liver fat and some metabolic markers than Mediterranean or low-fat plant-forward diets in adults with obesity, prediabetes and fatty liver disease.
“Participants on the keto diet saw liver fat fall by an average of 67%. The reductions in the Mediterranean and plant-forward groups averaged about 45%”
The findings, published in Cell Metabolism, add fresh detail to the debate over whether the composition of a weight-loss diet matters once calorie intake and weight reduction are broadly similar.
All three dietary approaches helped participants lose weight, reduce body fat and improve insulin sensitivity. Yet the very low-carbohydrate ketogenic plan produced the largest changes in liver fat, insulin levels and several measures of metabolic health.
The study was relatively small, involving 42 adults. Its design, however, gave researchers unusually close control over what participants ate. Every meal was supplied by the research team, reducing one of the biggest sources of uncertainty in nutrition research as to whether people can accurately follow and report a prescribed diet in daily life.
Participants had obesity, prediabetes and metabolic dysfunction-associated steatotic liver disease, often referred to as fatty liver disease. This combination is clinically important. Excess liver fat is linked with insulin resistance, type 2 diabetes, inflammation and, in some people, progressive liver damage. Improving liver health can therefore have consequences well beyond the organ itself.
Each person was randomly assigned to one of three eating patterns: a ketogenic diet, a Mediterranean-style diet or a low-fat, plant-forward diet. Researchers adjusted calorie intake individually, with the aim of helping each participant lose approximately 10% of their starting body weight over four to five months.
The ketogenic diet was extremely low in carbohydrate. It supplied about 4% of calories from carbohydrate and 73% from fat. The Mediterranean-style approach provided roughly 50% of calories from carbohydrate and 35% from fat. The plant-forward plan was highest in carbohydrate, contributing about 70% of calories, while fat represented about 15%.
All participants met weekly with a dietitian. The close supervision appears to have worked. By the end of the trial, the groups had achieved substantial weight reduction and significant falls in body fat. They also became more sensitive to insulin, meaning their bodies were better able to manage glucose in the bloodstream.
That result matters because insulin resistance sits at the centre of many metabolic conditions. When cells respond poorly to insulin, the pancreas often compensates by producing more of the hormone. Over time, this can contribute to persistently raised blood glucose, increasing the risk of type 2 diabetes. It can also promote fat storage in the liver.
Weight loss itself remains a powerful explanation for many of the improvements observed across the three groups. Losing around 5% to 10% of body weight can improve blood pressure, blood glucose regulation, triglycerides and liver fat in many people.
The trial nevertheless indicates that a ketogenic diet may exert additional effects in people with fatty liver disease and prediabetes, even when total weight loss is designed to be comparable.
The largest difference emerged in liver fat. Participants on the keto diet saw liver fat fall by an average of 67%. The reductions in the Mediterranean and plant-forward groups averaged about 45%. All are substantial changes. The keto result, though, suggests that sharply reducing carbohydrate intake may affect how the liver handles fat.
The researchers also carried out 24-hour metabolic testing, taking repeated blood samples to observe changes in hormones and fuel use throughout the day. The ketogenic group showed the greatest increase in glucagon, a hormone that can encourage the liver to release stored energy and may support reductions in liver fat under some conditions. It also had the largest fall in circulating insulin levels.
Lower insulin concentrations may be relevant for fatty liver disease because insulin can encourage fat production and storage in the liver when present at persistently high levels. A diet that lowers post-meal glucose and insulin demand could therefore offer a metabolic advantage for selected patients.
Another notable finding was the change in prediabetes status. By the end of the intervention, around half of participants following the ketogenic diet no longer met the criteria for prediabetes. This compared with 29% in the Mediterranean group and 7% in the plant-forward group.
These figures are attention-grabbing, although they should be interpreted carefully.
The study was not large enough to establish that keto is universally superior for reversing prediabetes. The follow-up period was also short. Whether the differences remain after one year, two years or longer is unknown.
Researchers noted that the keto group did not show the rise in blood fats or cholesterol that some clinicians might expect from a diet containing a high proportion of fat. That result is encouraging, but it does not mean that every ketogenic diet is heart healthy. Food quality remains crucial.
A keto diet based largely on processed meats, butter, refined oils and low-fibre packaged products is very different from one centred on fish, eggs, olive oil, nuts, seeds, avocado, non-starchy vegetables and minimally processed foods.
The study also does not overturn the extensive evidence supporting Mediterranean-style eating.
Mediterranean diets have a long record in research on cardiovascular health, diabetes prevention and overall dietary quality. They are rich in vegetables, fruit, pulses, whole grains, nuts, olive oil and fish, while generally limiting ultra-processed foods and excess red meat. Their moderate nature may make them easier for many people to maintain over years rather than months.
Sustainability is one of the central questions raised by the new findings. A ketogenic diet can be restrictive. Bread, rice, pasta, potatoes, many fruits, beans and most sweets are limited or excluded in strict versions of the approach. Social meals become more complicated. Eating out requires planning. Some people experience constipation, headaches, fatigue or other symptoms while adapting to a sharp fall in carbohydrate intake.
For others, the structure can be useful. The diet may reduce appetite for some people, simplify meal choices and lead to fewer blood sugar swings. Responses vary widely. A diet that improves one person’s glucose levels may be impractical, unpleasant or medically unsuitable for another.
The plant-forward diet in the trial also deserves context. It was low in fat and high in carbohydrate, yet still produced weight loss, body-fat reduction and improved insulin sensitivity. Plant-forward eating is not synonymous with high-quality eating, however. The nutritional outcome depends on the specific foods selected. A plan built around vegetables, pulses, whole grains, nuts, fruit and minimally processed staples differs markedly from one dominated by refined grains, sugary foods and highly processed meat substitutes.
There were several limitations. The group of 42 participants was small. All had a particular cluster of health conditions: obesity, prediabetes and fatty liver disease. The findings may not apply to people without these conditions, to older adults, to adolescents, to those who are pregnant, or to people taking medicines that require closer dietary management.
The intervention lasted only four to five months. This is long enough to show meaningful changes in body weight and metabolic measures. It is not long enough to determine whether a dietary pattern reduces heart attacks, strokes, cirrhosis, diabetes complications or mortality. It also cannot fully answer whether participants could comfortably maintain the approach after meals and weekly dietitian support ended.
Muscle-related benefits were similar across all three dietary groups, according to the study expert. That reinforces a key message: weight reduction was a major driver of improvement regardless of dietary pattern. Muscle is a major site of glucose disposal, so preserving it during weight loss is important. Adequate protein intake, resistance exercise and avoiding overly rapid or severe calorie restriction can help protect lean mass.
For people considering a ketogenic diet, medical supervision is sensible, particularly where diabetes, kidney disease, liver disease, high cholesterol, eating disorders or medication use are involved. Those taking insulin or medicines that increase insulin release may need dose adjustments to avoid hypoglycaemia (very low blood sugar level). People using sodium-glucose cotransporter-2 inhibitors (medication) should seek clinical advice before attempting a ketogenic diet because of a risk of ketoacidosis, including cases in which blood glucose is not severely elevated.
The study’s practical lesson is not that one diet has defeated all others. It is more nuanced.
Weight loss improved metabolic health across every group. Yet, in this closely monitored trial, a ketogenic diet appeared to offer an extra short-term benefit for liver fat and some measures of glucose regulation among adults with obesity, prediabetes and fatty liver disease.
That may make keto a reasonable clinical option for carefully selected people, especially when fatty liver disease and elevated insulin levels are major concerns. It should not be treated as a universal prescription.
A successful diet needs to be nutritionally adequate, medically safe and realistic enough to continue.
Mediterranean and plant-forward patterns remain strong, evidence-based choices. Keto may offer a potent alternative for some patients.
The best plan is likely to be the one that improves health markers, supports a sustained calorie deficit where weight loss is needed, protects nutritional quality and fits into ordinary life.
The post Keto, Mediterranean or Plant-Forward Diet? Trial Finds Keto Led on Liver Fat Loss first appeared on PP Health Malaysia.