Low-Carb vs. Mediterranean Diets
Mediterranean and low-carbohydrate diets are both widely used approaches to healthy eating, but they differ substantially in the amount of carbohydrate they contain.
A Mediterranean diet emphasizes vegetables, fruits, legumes, whole grains, nuts, olive oil, and fish. It has extensive research supporting cardiovascular health and is widely recommended by medical organizations.
A low-carbohydrate diet reduces sugars and starches and generally emphasizes protein, fats, and non-starchy vegetables. Very-low-carbohydrate ketogenic diets reduce carbohydrates enough to produce ketones.
The two approaches overlap considerably. Both can emphasize vegetables, fish, nuts, olive oil, minimally processed foods, and avoiding added sugars and ultra-processed foods.
The important question may not be which diet is universally best, but which works best for which person.
A Major Head-to-Head Trial
A 2026 randomized clinical trial compared three diets in people with obesity, prediabetes, and excess liver fat:
Very-low-carbohydrate ketogenic
Mediterranean
Very-low-fat, plant-forward
Researchers provided all the food, and participants lost about 10% of their body weight on each diet.
All three diets improved metabolic health. But despite similar weight loss, the ketogenic diet produced greater improvements in several measures, including liver fat, hepatic insulin resistance, HbA1c, and 24-hour glucose and insulin levels.
Muscle insulin sensitivity improved by about 50% with all three diets, but improvement in liver insulin sensitivity was two to three times greater with keto.
Prediabetes remission occurred in 50% of the keto group, 29% of the Mediterranean group, and 7% of the very-low-fat group. Because only 42 people completed the study, these percentages should be interpreted cautiously.
Read the Study — Effect of Diet Macronutrient Content on the Cardiometabolic Response to Weight Loss
Did Keto Win?
Nick Norwitz summarized the study with the provocative headline “Keto Won.”
On several metabolic measures, keto clearly produced the largest improvements. Interestingly, despite consuming much more saturated fat, the keto group did not have a significantly worse change in LDL cholesterol or ApoB than the other groups.
But the study was small and relatively short, and all participants had obesity, prediabetes, and excess liver fat. It does not establish that keto is better for metabolically healthy people or that its advantages persist for years.
Nor does one trial overturn the extensive evidence supporting Mediterranean-style eating, particularly for cardiovascular health.
What the study does suggest is that metabolic health may matter when choosing a diet.
Nick Norwitz, M.D., Ph.D. — A Major Trial Put Keto Against the Mediterranean Diet. Keto Won.
Norwitz discusses the study and argues that its results illustrate why the healthiest diet may depend partly on an individual’s metabolic condition.
Key Takeaways
Both Mediterranean and low-carbohydrate diets can be healthy.
Mediterranean eating has extensive evidence supporting cardiovascular health.
Low-carbohydrate diets can be particularly useful for blood glucose, triglycerides, weight, and Insulin Resistance.
In this study, keto produced greater improvements in several metabolic measures despite similar weight loss.
The study was small and involved people with significant metabolic problems.
Rather than asking which diet is universally best, it may be more useful to ask: Which diet works best for which person?
Learn More
American Heart Association — Mediterranean Diet
An overview of Mediterranean-style eating and its cardiovascular benefits.
American Diabetes Association — Eating for Diabetes Management
Information about dietary approaches for managing diabetes, including carbohydrate reduction.
Precision Nutrition & Metabolic Health
A 2026 review examining why differences in Insulin Resistance, glucose metabolism, genetics, and the gut microbiome may influence how people respond to different diets.
Videos
Keto vs. Mediterranean — Which Is Better? - 24 Minutes
A discussion of research comparing ketogenic and Mediterranean diets and how metabolic health can affect the interpretation of the results.
Mediterranean or Keto — Does It Matter? | Dr. David Katz - 10 Minutes
Dr. David Katz discusses Mediterranean and ketogenic diets and the importance of overall diet quality.
Gary Taubes — The Case for a Ketogenic Diet - 47 Minutes
Gary Taubes makes the case for carbohydrate restriction, focusing on insulin, fat storage, and metabolic health.