Same weight loss, bigger liver benefits on low carb

Researchers at Washington University School of Medicine in St. Louis randomly assigned 55 adults with obesity, prediabetes and fatty liver to one of three diets for about five months: a low-carb, high-fat ketogenic diet; a high-carb, low-fat, plant-forward diet; or a Mediterranean diet in between. Participants were given all their food and met weekly with a dietitian. The results appeared in Cell Metabolism.

All three groups lost about the same amount of weight—roughly 10% of their starting weight—and improved insulin sensitivity in their muscles by about 50%. Losing weight helped no matter which diet got them there.

The differences showed up in the liver. Liver fat dropped 67% on the ketogenic diet compared with 45% on the other two. Liver insulin sensitivity improved two to three times more on keto.

Blood sugar followed the same pattern: 24-hour glucose fell 20% on keto versus 8% on the other diets. Half of the low-carb group reversed their prediabetes, compared with 29% on the Mediterranean diet and 7% on the high-carb diet.

What it means on the road: this was a small, short study where every meal was provided—real life at a fuel stop is harder. Still, it suggests that for drivers carrying extra weight with high blood sugar, cutting carbs may help the liver beyond the number on the scale.

If you take diabetes medication or have liver disease, talk with your clinician before starting a very-low-carb diet.