The Popular Diet That Cuts Liver Fat by 67 Percent

Key takeaways

• In a clinical trial comparing three well-known eating patterns, participants following a very low-carbohydrate, high-fat approach saw liver fat drop by 67%, compared with a 45% reduction on both a Mediterranean-style diet and a low-fat, plant-forward diet.
• All three groups lost the same amount of body weight — about 10% — meaning the extra benefit to liver fat and blood sugar regulation came from the diet's makeup, not from losing more weight.
• About half of participants following the lower-carbohydrate approach saw their blood sugar regulation return to a healthier range, compared with smaller shares on the other two diets, suggesting that what you eat may matter beyond calories alone.

Same weight loss, different results

Researchers have generally accepted that shedding excess body weight improves metabolic health, but they've had far less clarity on whether the composition of a diet — how much comes from carbohydrates versus fat — adds any benefit beyond weight loss itself. A new clinical trial set out to answer that directly by comparing three distinct, popular approaches head-to-head under carefully controlled conditions.

Researchers enrolled 42 participants with elevated liver fat and blood sugar regulation concerns, then randomly assigned each person to follow one of three diets for four to five months: a very low-carbohydrate, high-fat approach (about 4% carbohydrates, 73% fat), a Mediterranean-style pattern (50% carbohydrates, 35% fat, built around vegetables, olive oil, fish, and moderate dairy), or a low-fat, plant-forward diet (70% carbohydrates, 15% fat). The research team supplied all meals and had participants meet weekly with a dietitian to help them stay on track. Calorie intake was individually adjusted so that everyone in all three groups would lose roughly the same amount of weight — about 10% of body weight.

Where the diets diverged

By the end of the trial, everyone had reduced body fat and improved insulin sensitivity, the measure of how effectively the body manages blood sugar. But liver fat told a very different story depending on which diet people followed. The very low-carbohydrate group saw liver fat drop by an average of 67%, nearly 1.5 times the 45% reduction seen in both other groups, despite everyone losing comparable weight.

Blood tests over a full 24-hour period offered a clue as to why. Participants on the very low-carbohydrate diet showed the largest rise in glucagon, a hormone that helps the body clear fat out of the liver, along with the steepest drop in circulating insulin — both changes that tend to support lower liver fat. Researchers were also surprised that this group didn't see any rise in blood fat or cholesterol levels, despite eating the most fat of the three groups by far.

The blood sugar payoff

The clearest functional benefit showed up in blood sugar regulation. About half of the participants following the very low-carbohydrate diet moved into a healthier blood sugar range by the end of the trial, compared with 29% on the Mediterranean diet and just 7% on the low-fat, plant-forward diet.

That's a meaningful gap given that all three groups lost essentially the same amount of weight. It suggests that for people carrying excess liver fat alongside blood sugar regulation challenges, the specific mix of carbohydrates and fat in a diet can meaningfully shift outcomes on top of whatever benefit comes from weight loss alone.

The takeaway

This trial adds real precision to a question that's mostly been argued anecdotally: does diet composition matter beyond the number on the scale? Here, the answer looks like yes — at least for liver fat and blood sugar regulation, and at least for people who started the trial with elevated levels of both. A very low-carbohydrate, higher-fat approach outperformed two other well-regarded diets on these specific measures, even though everyone lost the same amount of weight.

That doesn't make any one diet the universal answer — the Mediterranean and plant-forward groups still saw real, meaningful improvements too. But it's a useful reminder that when metabolic health is the goal, how you get to a lower number on the scale may matter just as much as getting there at all.

References:

Max C. Petersen, Gordon I. Smith, Sarah S. Farabi, et al. Effect of diet macronutrient content on the cardiometabolic response to weight loss: A randomized clinical trial. Cell Metabolism, 2026. DOI: 10.1016/j.cmet.2026.07.020.