Scientists at Washington University School of Medicine in the United States have found that a ketogenic low-carb diet can reverse prediabetes within five months. The eating regime proved more effective at putting the chronic condition into remission than both a Mediterranean diet and a traditional low-fat diet.
According to the study published in the journal Cell Metabolism, half of participants with prediabetes who followed a low-carb diet no longer met the criteria for the condition after five months. By comparison, only a third of participants on a Mediterranean diet and seven per cent of those in a low-fat group achieved prediabetes remission.
Researchers found that all three eating plans resulted in the same average weight loss of around 10 per cent of body weight over four to five months. However, the low-carb diet delivered superior benefits for liver health and blood sugar control.
The low-carb diet, made popular by celebrities including Kourtney Kardashian and Gwyneth Paltrow, was also found to reduce the risk of fatty liver disease. The condition has seen a fivefold increase over the past decade and is believed to be widely underdiagnosed in healthcare settings.
"If you have prediabetes, reducing carbohydrate intake can have important effects on metabolism beyond just weight loss alone," said Dr Samuel Klein, lead author of the study.
Prediabetes is a metabolic condition where blood sugar levels are elevated above normal but not yet high enough to be diagnosed as type 2 diabetes. It acts as a major precursor to full diabetes while increasing the long-term risk of heart disease, stroke, and liver damage. In the United Kingdom, up to 6.3 million people are estimated to live with prediabetes.
Comparing diet plans and trial results
To compare the eating styles, researchers at Washington University School of Medicine tracked 42 adult participants diagnosed with obesity, prediabetes, and fatty liver disease. Participants were randomly split into three groups to follow a ketogenic diet, a Mediterranean-style diet, or a low-fat plant-based diet.
The research team provided all meals directly to trial participants throughout the study. Attendees also met weekly with a registered dietician to support strict compliance with their assigned eating plans.
The three eating styles differed significantly in their nutritional composition. The ketogenic diet sourced 73 per cent of daily energy from fat and allocated just four per cent of daily calories to carbohydrates. Conversely, the low-fat diet prioritized carbohydrates, obtaining 70 per cent of calories from plant foods such as lentils, rice, and potatoes. A Mediterranean diet traditionally emphasizes fish, healthy fats like olive oil and nuts, alongside fibrous fruits and vegetables.
While all three dietary approaches improved blood sugar control and lowered diabetes risk, the ketogenic diet produced marked improvements in liver metabolism. Diabetes develops when the human body grows resistant to insulin or fails to produce enough of the hormone, which is responsible for moving glucose out of the bloodstream and into cells for energy.
Participants following the ketogenic plan experienced a 67 per cent drop in liver fat after five months. In contrast, participants in the Mediterranean and low-fat diet groups saw a 45 per cent reduction in liver fat. Continuous 24-hour blood monitoring revealed that the ketogenic diet triggered the largest rise in glucagon, a hormone that signals the liver to burn stored fat.
Surprise cholesterol findings and expert reaction
High-fat ketogenic diets have previously raised concerns over potential increases in blood cholesterol levels due to their high fat content. However, trial data showed no negative impact on blood lipid profiles despite the high fat intake.
"The most surprising finding was that participants in the keto diet group didn't experience an increase in blood fat or cholesterol levels, despite consuming the most fat," Dr Klein said.
"Weight loss drugs have revolutionised the treatment of obesity, helping users achieve significant weight loss," Dr Klein added. "But in addition, our study shows that the specific composition of a diet can give you added benefits."
Independent medical experts have welcomed the research findings while noting the primary importance of overall weight reduction. Dr Adam Collins, a professor of nutrition at the University of Surrey who was not involved in the trial, emphasized the central role of weight loss.
"In summary, the study emphasises that achieving meaningful weight loss is crucial," Dr Collins said. "Although the ketogenic diet offers unique benefits for liver metabolism, it shows little evidence of a broader metabolic advantage over other diets in terms of fat loss and cardiovascular risk. The primary driver of improved health was losing 10 per cent of body weight."
Rise of fatty liver disease and diabetes in the UK
The study arrives amidst growing concern over a hidden epidemic of metabolic dysfunction-associated steatotic liver disease, known medically as MASLD or fatty liver disease. Diagnostic rates for the illness have surged fivefold over the last decade, and experts warn that millions of cases remain undetected across the country.
Fatty liver disease is frequently termed a silent killer because it produces few noticeable symptoms during early development. If left unmanaged, the build-up of fat in liver cells can lead to irreversible liver damage, cirrhosis, liver failure, and liver cancer. Healthcare experts emphasize that lifestyle modifications, including diet and weight loss, can halt or reverse early-stage liver damage before permanent harm occurs.
Type 2 diabetes currently affects more than four million people in the UK, with roughly one in three adults in England living with obesity, a primary driver of the illness. Excess liver fat impairs the body's ability to regulate blood sugar and heightens resistance to insulin, aggravating diabetes progression.
Common symptoms of type 2 diabetes include persistent fatigue, increased thirst, and frequent urination. Over time, unmanaged high blood sugar can damage nerves, impair vision, and elevate the risk of heart attack or stroke. While initial treatment focuses on dietary changes and weight control, severe cases often require long-term medical management.
