All three diets improved body fat and insulin sensitivity after about 10% weight loss, but the ketogenic diet produced the largest short-term improvements in liver fat and several blood-sugar measures. Liver fat fell 67% with the ketogenic diet, compared with 45% on both Mediterranean and very-low-fat plant-forward diets, despite closely matched weight loss. The tightly controlled trial was small and lasted only several months, so it cannot establish the long-term health effects or sustainability of a ketogenic diet. Losing about 10% of body weight improved metabolic health regardless of whether people ate ketogenic, Mediterranean or very-low-fat diets. Yet once researchers held weight loss nearly equal, the composition of those diets still made a measurable difference. A randomized clinical trial at Washington University School of Medicine compared the three approaches in adults with obesity, prediabetes and fatty liver disease. Forty-two participants completed the intervention, with 14 in each diet group. The ketogenic group showed the largest reductions in liver fat, daily glucose and insulin exposure and several other metabolic measures. About half also no longer met …