Study Finds Keto, Mediterranean and Plant-Forward Diets All Support Weight Loss, but Keto Shows Larger Liver-Fat Reduction

By Arizona Asians Staff

A new clinical trial from Washington University School of Medicine in St. Louis found that three popular diets — ketogenic, Mediterranean and low-fat plant-forward — helped adults with obesity lose similar amounts of weight. But the ketogenic diet showed a larger reduction in liver fat and stronger improvements in some blood-sugar measures.

The study, published August 27, 2026, in Cell Metabolism, followed adults with obesity, prediabetes and fatty liver disease for about four to five months. Participants were assigned to one of three diets and received all of their food from the research team, helping researchers more closely compare the effects of each eating plan.

All Three Diets Helped With Weight Loss

Researchers found that participants in all three diet groups lost about 10% of their starting body weight. All three groups also improved muscle insulin sensitivity, an important measure of how well the body uses insulin to regulate blood sugar.

The findings suggest that weight loss itself remains one of the most important factors in improving metabolic health for people with obesity, prediabetes and fatty liver disease.

Keto Diet Showed Greater Liver Benefits

While all three diets improved health markers, the ketogenic diet produced the largest reduction in liver fat.

According to the study, liver fat decreased by an average of 67% in the ketogenic diet group, compared with about 45% in both the Mediterranean and plant-forward diet groups.

The ketogenic group also showed greater improvement in liver insulin sensitivity and 24-hour blood glucose levels. Researchers said the very low-carbohydrate approach may help reduce insulin levels and shift metabolism in ways that reduce fat buildup in the liver.

Prediabetes Improvements Also Noted

The study reported that about 50% of participants in the ketogenic group no longer met the criteria for prediabetes after the intervention. That compared with about 29% in the Mediterranean group and 7% in the plant-forward group.

Researchers emphasized, however, that all three diets led to meaningful benefits through weight loss.

What This Means for Families

The study does not mean everyone should immediately switch to a ketogenic diet. Keto can be highly restrictive and may not be appropriate for people with kidney disease, certain heart conditions, pregnancy, eating-disorder history or other medical concerns.

The Mediterranean and plant-forward diets may be easier for many people to follow long term and are also associated with broader heart-health and lifestyle benefits.

For people with fatty liver disease, obesity or prediabetes, the most practical takeaway is to speak with a doctor or registered dietitian before making major diet changes. The best diet is one that is medically safe, nutritionally balanced and sustainable.

The study was relatively short and focused on a specific group of adults with obesity, prediabetes and fatty liver disease. Longer studies are needed to understand whether the benefits continue over time and how well people can maintain each diet outside a controlled research setting.

Still, the findings add useful evidence to an important health discussion: while losing weight improves metabolic health, the type of diet may also matter for specific conditions such as fatty liver and prediabetes.
Exercise Can Strengthen the Benefits of Healthy Eating

While the study focused on diet, regular physical activity can often improve the results people see from any healthy eating plan. Exercise helps the body use insulin more effectively, supports blood-sugar control, preserves muscle during weight loss and improves heart health. For people with obesity, prediabetes or fatty liver disease, combining a nutritious diet with consistent movement may lead to stronger long-term health benefits than diet changes alone.

Even moderate activity can help. Walking, cycling, swimming, strength training, yoga or other forms of movement can support weight management and overall metabolic health. Strength training is especially useful because it helps maintain lean muscle, which plays an important role in how the body processes glucose and burns energy.

Health experts generally recommend choosing activities that are safe, enjoyable and sustainable. People with medical conditions, severe obesity, liver disease, heart concerns or limited mobility should speak with a healthcare professional before starting a new exercise routine.

The key message is balance: a healthy diet can support weight loss and liver health, while regular exercise can help the body become stronger, more resilient and better able to maintain those improvements over time.