Keto Diet Liver Fat Fell 67% in New Study
The keto diet liver fat findings from a new clinical trial are giving researchers another reason to look beyond the number on the scale. A study published in the peer-reviewed journal Cell Metabolism found that three different diets produced similar weight loss, but a ketogenic diet delivered substantially greater improvements in liver fat and several measures of metabolic health.
The randomized clinical trial compared a very low-carbohydrate ketogenic diet with a Mediterranean diet and a high-carbohydrate, low-fat plant-forward diet. Participants in all three groups lost about 10% of their starting body weight over roughly five months.
Yet the results were not identical once researchers examined what was happening inside the body.
The ketogenic group experienced an average 67% reduction in liver fat, compared with about 45% in both the Mediterranean and plant-forward groups. The keto group also recorded stronger improvements in liver insulin sensitivity, blood glucose and insulin levels.
The findings do not mean that keto is automatically the best diet for everyone. The participants had a specific combination of obesity, prediabetes and excess liver fat. Still, the results suggest that the composition of a diet may influence certain health outcomes beyond weight loss alone.
Why Keto Diet Liver Fat Results Stand Out
Weight loss is widely recognized as an important way to improve metabolic health. However, researchers have not always known whether the amount of carbohydrate, fat and protein in a diet makes a meaningful difference once people lose the same amount of weight.
The new trial was designed to address that question.
Researchers at Washington University School of Medicine in St. Louis randomly assigned adults with metabolically unhealthy obesity to three different dietary approaches. The participants had elevated blood sugar and excess fat in their livers, placing them at increased risk for more serious metabolic problems.
The diets were intentionally very different.
The ketogenic plan was extremely low in carbohydrates and high in fat. The Mediterranean plan provided a more balanced mix of carbohydrates and fat, while the plant-forward diet was high in carbohydrates and low in fat.
Importantly, researchers supplied 100% of the participants’ food during the intervention and provided weekly support from dietitians. That level of control allowed the research team to study the effects of the diets more precisely than would typically be possible in a study where participants simply receive dietary advice.
Despite the major differences in macronutrient composition, all three groups lost approximately the same amount of weight.
That makes the liver findings particularly interesting.
All Three Diets Produced Similar Weight Loss
The headline result is not simply that keto produced weight loss.
In fact, the study found that all three diets worked for weight reduction.
Participants lost roughly 10% of their starting body weight during the approximately five-month intervention. Their muscle insulin sensitivity also improved by about 50% from baseline across the diet groups.
That finding reinforces an important point about nutrition research: there may be several effective ways to lose weight.
A person does not necessarily need to follow one specific diet structure to experience the metabolic benefits associated with losing excess weight.
However, the researchers observed important differences in what happened to the liver.
The ketogenic diet produced much larger improvements in liver insulin sensitivity and liver fat compared with the other two approaches.
The result suggests that weight loss itself was responsible for many of the improvements, while carbohydrate restriction may have provided additional benefits for certain metabolic processes.
Keto Diet Liver Fat Reduction Reached 67%
The most striking finding involved fat stored inside the liver.
Participants following the ketogenic diet experienced a 67% average reduction in liver fat. By comparison, liver fat decreased by approximately 45% among participants following both the Mediterranean and plant-forward diets.
Researchers also found that liver insulin sensitivity improved in all three groups, but the improvement was approximately two to three times greater among those following the ketogenic diet.
That matters because the liver plays a central role in regulating blood glucose and energy metabolism.
When the liver becomes resistant to insulin, it can continue producing glucose when the body does not need as much. This can contribute to elevated blood sugar and worsening metabolic health.
The new findings suggest that dramatically reducing carbohydrate intake may affect these processes in ways that go beyond the effect of losing body weight.
However, the study was relatively small and short. Therefore, the results should be viewed as promising evidence rather than proof that a ketogenic diet will produce the same outcome for everyone.
Blood Sugar Improvements Were Also Stronger
The differences were not limited to liver fat.
The ketogenic group also experienced greater improvements in blood sugar control. According to the research findings, 24-hour blood glucose levels decreased by approximately 20% from baseline among keto participants, compared with about 8% in the other diet groups.
Daily insulin levels also fell substantially.
The ketogenic group recorded an approximately 74% decrease in daily insulin levels, compared with 44% for the Mediterranean diet and 27% for the high-carbohydrate plant-forward diet.
The researchers noted that very low carbohydrate intake naturally reduces the amount of insulin needed to regulate blood glucose.
That does not necessarily mean that everyone should drastically cut carbohydrates. Rather, it highlights how different macronutrient combinations can produce different physiological responses even when weight loss is similar.
Keto Also Produced More Prediabetes Remission
Another notable result involved prediabetes.
About half of the participants in the ketogenic group no longer met the study criteria for prediabetes after the intervention. That compared with approximately 29% in the Mediterranean group and 7% in the plant-forward group.
This finding is significant because prediabetes can increase the risk of developing Type 2 diabetes.
Still, the percentages should be interpreted cautiously.
The trial involved a relatively small number of participants with specific metabolic characteristics. A result observed in this population cannot automatically be applied to people who do not have obesity, prediabetes or excess liver fat.
Longer and larger clinical trials will be needed to determine whether the apparent advantage remains over time.
What Makes the Ketogenic Diet Different?
The ketogenic diet works by severely limiting carbohydrate intake.
When carbohydrate availability becomes very low, the body changes how it obtains and uses energy. Fat becomes a much more important fuel source, and the liver produces ketones that can be used by various tissues.
The diet used in the new trial was particularly restrictive. According to reporting on the study, roughly 4% of calories in the ketogenic group came from carbohydrates, while about 73% came from fat. The Mediterranean and plant-forward diets had substantially different macronutrient profiles.
That distinction is important.
The study did not test a moderate low-carb eating plan against another moderately healthy diet. It tested three intentionally different dietary patterns.
Therefore, readers should not assume that simply reducing bread, pasta or sugar will reproduce the exact 67% liver-fat reduction seen in the trial.
The Mediterranean Diet Still Delivered Benefits
The study should not be interpreted as evidence that the Mediterranean diet failed.
Quite the opposite.
Participants following the Mediterranean diet also lost about 10% of their body weight and experienced improvements in metabolic health. Liver fat fell by approximately 45%, and nearly one-third of participants achieved prediabetes remission.
The Mediterranean diet is also widely recognized for emphasizing foods such as vegetables, fruits, legumes, whole grains, nuts, fish and other minimally processed foods.
The new research instead adds another layer to the discussion.
For people with specific metabolic problems, particularly excess liver fat and prediabetes, the macronutrient composition of a weight-loss diet may influence some outcomes more strongly than others.
That is a more nuanced conclusion than simply declaring one diet the universal winner.
The Plant-Forward Diet Worked Too
The high-carbohydrate, low-fat plant-forward diet also produced substantial benefits.
Participants lost approximately the same amount of weight as those in the other groups, while liver fat decreased by about 45%. Muscle insulin sensitivity also improved across the groups.
The findings therefore reinforce an important message: weight loss remains a powerful metabolic intervention.
Even when people follow very different diets, reducing excess body weight can improve insulin sensitivity and other markers associated with metabolic disease.
The keto diet’s apparent advantage was more specific. It appeared to provide additional improvements in liver metabolism and blood sugar regulation.
What the Study Does Not Prove
The headline about a 67% reduction in keto diet liver fat is compelling, but there are several reasons to avoid overinterpreting it.
First, the study population was specific. Participants had obesity, prediabetes and excess liver fat. The findings may not apply to healthy adults who simply want to lose a few pounds.
Second, the intervention lasted only about four to five months. That is enough time to observe meaningful biological changes, but it does not answer every question about long-term safety, adherence or effectiveness.
Third, participants received all of their food during the study.
That is a major strength from a research perspective, but it also makes the intervention different from real-world dieting. Most people must purchase, prepare and eat their own food while balancing work, family, social events and personal preferences.
A diet that performs extremely well under controlled research conditions may be more difficult to maintain in everyday life.
Researchers Say Diet Choice Still Matters
The study’s authors emphasized that weight loss remains beneficial regardless of which of the three dietary approaches produced it.
At the same time, their findings suggest that choosing a diet based solely on its ability to lower body weight may overlook important differences in metabolic outcomes.
Max C. Petersen, the study’s first author, said the findings indicate that diet choice can influence specific health outcomes beyond weight loss alone.
That could become increasingly important as doctors and researchers try to personalize treatment for obesity and metabolic disease.
Two people can lose the same amount of weight but experience different changes in blood sugar, insulin sensitivity or liver metabolism.
The new trial suggests that nutrition may play a role in those differences.
Could Keto Become a Tool for Fatty Liver?
The findings raise an important question about whether very low-carbohydrate diets could become a more targeted tool for people with obesity and fatty liver.
Researchers at WashU Medicine pointed to the high prevalence of fatty liver among adults with obesity and suggested that carbohydrate restriction could potentially provide additional therapeutic effects beyond weight loss.
The study also found changes in hormones and metabolic pathways that may help explain the liver results. The ketogenic group had the largest increase in glucagon, a hormone involved in energy metabolism, and the greatest reduction in circulating insulin.
Those changes may help explain why liver fat fell more sharply in the keto group.
Still, more research is necessary before the results can be translated into broad treatment recommendations.
What Readers Should Take Away
The biggest lesson from the study is not that everyone should immediately switch to keto.
Instead, it is that weight loss and diet composition can have overlapping but distinct effects.
All three diets produced significant weight loss. All three improved important aspects of metabolic health. But the ketogenic diet delivered additional improvements in liver fat, liver insulin sensitivity, blood glucose and insulin levels among this particular group of participants.
For people dealing with obesity, prediabetes or fatty liver, those differences could eventually help doctors create more personalized dietary strategies.
For everyone else, the study is a reminder that nutrition research is rarely as simple as choosing a single “best” diet.
The most effective approach depends on the person’s health, dietary needs, ability to follow the plan and long-term goals.
The Bottom Line on Keto Diet Liver Fat
The latest research provides a striking new finding: keto diet liver fat decreased by an average of 67% in participants with obesity, prediabetes and excess liver fat after roughly five months.
The Mediterranean and plant-forward diets also worked, with participants in all three groups losing about 10% of their starting weight. However, the ketogenic diet produced larger improvements in several liver and blood-sugar measurements.
The findings are encouraging, but they are not a prescription for everyone.
The trial was relatively small, the intervention was short, and participants received tightly controlled meals. More research will be needed to establish how these results translate to longer-term, real-world diets.
For now, the study adds an important twist to the weight-loss debate: the number on the scale may tell only part of the story. What people eat to reach that weight may also influence what happens inside the liver and how the body handles blood sugar.
People considering a ketogenic or other highly restrictive diet, particularly those with metabolic conditions or who take glucose-lowering medication, should discuss dietary changes with a qualified healthcare professional.
