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Low-carb diets and liver health: does reducing carbohydrates offer benefits beyond weight loss?
We often hear that the main reason low-carbohydrate diets improve metabolic health is that they help us lose weight. While weight loss can certainly improve insulin sensitivity, blood glucose control and fatty liver, an interesting new study suggests that what we eat may also influence metabolic health independently of how much weight we lose.
Published in Cell Metabolism in October 2026, a randomised clinical trial investigated how three very different dietary approaches affected metabolic health in people with obesity, prediabetes and excess fat in the liver.
The results were particularly interesting for anyone following a low-carbohydrate or ketogenic diet. Although all three diets produced similar weight loss, the ketogenic diet led to substantially greater improvements in several measures of liver health and glucose metabolism.
So, what did the researchers discover, and what might it mean for people following a low-carb diet?
The study: three diets, similar weight loss
The researchers recruited people with obesity who also had signs of metabolic ill health, including prediabetes and hepatic steatosis (fat accumulation in the liver).
Participants were randomly allocated to one of three diets:
Ketogenic diet: Very low in carbohydrate, providing approximately 4% of total energy from carbohydrates, 73% from fat and 23% from protein.
Mediterranean-style diet: Providing 50% of energy from carbohydrates, 35% from fat and 15% from protein.
Very-low-fat, plant-forward diet: Providing 70% of energy from carbohydrates, 15% from fat and 15% from protein.
An important feature of the trial was that all the food was provided to participants, helping the researchers maintain good dietary adherence. Compliance was reported to be above 95%.
The study analysed 42 participants who completed the intervention, with 14 people in each dietary group. Participants followed their assigned diet until they had lost approximately 10% of their starting body weight.
Crucially, all three groups achieved very similar weight loss:
Ketogenic diet: 10.4%
Mediterranean diet: 10.2%
Very-low-fat diet: 10.1%
This gave the researchers an opportunity to investigate whether the composition of the diet influenced metabolic improvements over and above the effects of losing weight.
Finding 1: The ketogenic diet produced greater improvements in liver insulin sensitivity
One of the most interesting findings concerned insulin sensitivity in the liver.
Insulin is a hormone that helps regulate blood glucose. When we eat carbohydrate, blood glucose rises and the pancreas releases insulin to help move glucose into cells and regulate its storage and production.
Insulin resistance occurs when cells and tissues become less responsive to insulin. The pancreas may compensate by producing more insulin, but over time this can contribute to persistently elevated blood glucose and the development of type 2 diabetes.
Importantly, insulin resistance does not affect every tissue in the same way.
The liver plays a central role in regulating blood glucose. It normally responds to insulin by reducing its own glucose production. When the liver becomes insulin resistant, this process becomes less effective, contributing to raised blood glucose, particularly between meals and overnight.
In this trial, all three diets improved skeletal muscle insulin sensitivity by approximately 50%. However, the ketogenic diet produced a substantially greater improvement in hepatic (liver) insulin sensitivity – approximately two to three times greater than the improvements seen with the Mediterranean and very-low-fat diets.
This suggests that carbohydrate restriction may have particular benefits for liver metabolism, even when weight loss is similar.
Finding 2: The ketogenic diet reduced liver fat more substantially
The study also measured intrahepatic triglycerides – essentially, the amount of fat stored inside the liver.
Excess liver fat is increasingly recognised as an important feature of metabolic dysfunction. It is closely associated with insulin resistance and can contribute to metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD).
All three diets reduced liver fat, but the reduction was considerably greater in the ketogenic group:
Ketogenic diet: approximately 67% reduction
Mediterranean diet: approximately 45% reduction
Very-low-fat diet: approximately 45% reduction
In other words, despite achieving almost identical weight loss, participants following the ketogenic diet experienced a much larger reduction in liver fat.
Why might this happen?
One possible explanation relates to a process called de novo lipogenesis (DNL). This is the process by which the liver converts excess carbohydrate, particularly when energy intake is high, into fatty acids that can be stored as fat.
The researchers found that hepatic de novo lipogenesis decreased most in the ketogenic group.
A very-low-carbohydrate diet reduces the amount of carbohydrate available for this process and changes the body's use of fuels. This may help explain why liver fat decreased more substantially in the ketogenic group.
It is worth emphasising that liver fat can also be reduced through weight loss and improvements in overall diet quality. The study does not suggest that carbohydrate is the only cause of fatty liver, or that everyone with fatty liver needs to follow a ketogenic diet.
Finding 3: Blood glucose and insulin levels improved more with carbohydrate restriction
The ketogenic diet also produced greater improvements in several measures of glucose metabolism.
Participants following the ketogenic diet experienced larger reductions in:
HbA1c, a measure of average blood glucose over approximately two to three months.
24-hour glucose levels, measured using repeated glucose sampling.
Insulin levels over 24 hours.
The reduction in insulin was particularly interesting. The researchers found that it was associated with both reduced insulin secretion and increased insulin clearance.
This is relevant because people with insulin resistance often have to produce more insulin to maintain normal blood glucose levels. Reducing the demand for insulin may therefore be an important part of improving metabolic health.
The proportion of participants whose prediabetes went into remission also differed between the groups:
Dietary approach | Prediabetes remission |
Ketogenic | 50% |
Mediterranean | 29% |
Very-low-fat | 7% |
These findings are encouraging, although the small number of participants means that the percentages should be interpreted cautiously.
They do, however, add to the evidence that carbohydrate restriction can be a useful dietary strategy for improving glucose regulation in some people with metabolic dysfunction.
Finding 4: Changes in triglycerides and inflammation
The researchers also examined blood lipids and markers associated with inflammation and oxidative stress.
Fasting triglycerides decreased most in the ketogenic group. This is consistent with other research suggesting that reducing carbohydrate intake can be particularly effective at lowering elevated triglycerides in some people.
However, the findings were not uniformly better across every lipid marker. There were no significant differences between the three diets in LDL cholesterol, apolipoprotein B (apoB) or 24-hour plasma triglyceride concentrations.
This is an important distinction. A ketogenic diet can improve some aspects of the lipid profile, but individual responses vary. It should not be assumed that everyone will experience improvements in every cholesterol marker.
The ketogenic group also experienced reductions in several markers associated with inflammation and oxidative stress, including TNF-alpha, plasminogen activator inhibitor-1 (PAI-1) and urinary 8-isoprostane.
IL-6, another inflammatory marker, did not change significantly in any of the groups.
These findings raise interesting questions about whether carbohydrate restriction and improvements in liver metabolism may also influence inflammatory processes. However, this was a relatively small and short study, so further research is needed before drawing firm conclusions about longer-term inflammatory benefits.
Why might carbohydrate restriction have these effects?
The results suggest that the benefits of a ketogenic diet may extend beyond simply reducing calorie intake and body weight.
Several interconnected changes may help explain the findings.
1. Lower insulin demand
Reducing carbohydrate intake generally reduces the need for insulin secretion after meals. This can be particularly relevant for people who already have insulin resistance and elevated insulin levels.
2. Reduced liver fat production
With less carbohydrate available, the liver has less substrate for de novo lipogenesis – the conversion of carbohydrate into fat. This may contribute to the greater reduction in liver fat observed in the ketogenic group.
3. Changes in fuel utilisation
When carbohydrate intake is very low, the body adapts to using more fat as a fuel. The liver increases fatty acid oxidation and produces ketones, which can be used by various tissues as an alternative energy source.
4. Changes in metabolic hormones
The researchers observed changes in the balance between insulin and glucagon. In the ketogenic group, glucagon and the glucagon-to-insulin ratio increased, whereas they decreased in the other groups.
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These hormonal changes are part of the body's adaptation to very-low-carbohydrate eating and may contribute to changes in how the liver handles glucose and fat.
Taken together, these mechanisms provide a plausible explanation for why the ketogenic diet produced greater improvements in some aspects of liver and glucose metabolism, even though weight loss was similar across the groups.
Does this mean ketogenic diets are better than other diets?
Not necessarily.
The study provides interesting evidence that dietary composition matters, particularly for liver fat and hepatic insulin sensitivity. However, there are several important limitations.
The study was small. Only 42 participants completed the trial, with 14 in each dietary group. Larger studies are needed to establish how reliable and widely applicable the findings are.
The intervention was relatively short. Participants followed the diets for approximately four to five months. We do not yet know whether the differences would persist over several years or translate into fewer cases of diabetes, cardiovascular disease or liver complications.
The ketogenic diet was extremely low in carbohydrate. It provided just 4% of total energy from carbohydrate. This is a much more restrictive approach than a typical moderate low-carb diet. We cannot assume that eating 50–100 g of carbohydrate per day, for example, would produce the same results.
Food was provided throughout the trial. This helped achieve excellent adherence, but may not reflect the challenges of following a restrictive diet in everyday life.
Finally, the study involved people with obesity, prediabetes and fatty liver. Its findings cannot automatically be applied to people who are metabolically healthy, have a normal body weight or have different health needs.
What does this mean if you follow a low-carb diet?
For people who already follow a low-carbohydrate diet, this research offers some encouraging insights.
It reinforces the idea that carbohydrate restriction may influence metabolic health in ways that go beyond weight loss alone. In particular, it highlights the potential importance of liver insulin sensitivity and liver fat when considering the benefits of dietary change.
However, it is important not to focus exclusively on how low you can take your carbohydrate intake.
A well-formulated low-carb diet should still provide adequate protein, fibre, vitamins, minerals and essential fats. The quality of the foods you eat matters.
A practical approach might include:
Plenty of non-starchy vegetables, providing fibre and a range of protective plant compounds.
Adequate protein from foods such as fish, eggs, poultry, meat, tofu and other suitable sources.
Healthy fats from olive oil, avocados, nuts, seeds and oily fish.
Minimally processed foods rather than relying heavily on low-carb packaged products.
A variety of fibre-rich, lower-carbohydrate plant foods to support gut health.
Limiting excess alcohol and highly processed foods, both of which can be relevant to liver and metabolic health.
It is also worth monitoring your individual response. Depending on your health circumstances, this might include HbA1c, fasting glucose, triglycerides, HDL cholesterol, LDL cholesterol, apoB and, where clinically appropriate, assessment of liver health.
People taking glucose-lowering medication, particularly insulin or sulfonylureas, should seek medical advice before making substantial reductions in carbohydrate intake, as medication doses may need adjusting. Anyone with existing liver disease or other significant health conditions should also discuss dietary changes with their healthcare professional.
The take-home message
This study adds to the growing evidence that the macronutrient composition of our diet can influence metabolic health independently of weight loss.
Although all three diets produced similar reductions in body weight and improved muscle insulin sensitivity, the ketogenic diet achieved greater improvements in liver insulin sensitivity, liver fat, hepatic fat production and several measures of glucose regulation.
For people with insulin resistance, prediabetes or excess liver fat, this suggests that a very-low-carbohydrate approach may offer specific metabolic advantages.
However, this does not mean that everyone needs to follow a ketogenic diet. A moderate low-carb or Mediterranean-style approach may still provide substantial benefits, and long-term sustainability, nutritional adequacy and individual health needs remain important considerations.
Perhaps the most important message is that metabolic health is about more than the number on the scales. How our liver processes glucose and fat, how much insulin we need to produce, and how effectively our tissues respond to insulin are all important parts of the picture.
For those following a low-carb lifestyle, this research provides another interesting reason to look beyond weight loss and consider the wider metabolic benefits of dietary choices.
Research reference
Petersen MC et al. (2026). Effect of diet macronutrient content on the cardiometabolic response to weight loss: A randomized clinical trial. Cell Metabolism, 38, 2006–2017. Published 6 October 2026.
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