A six-month controlled feeding study compared diets with 20% fat (high carb), 30% fat (medium carb), or 40% fat (low carb), with constant protein and fiber.

“there was a low fat high carb diet a medium fat medium carb diet and a high fat low carb diet but the thing that they changed in all these diets was the amount of fat relative to the amount of carbohydrate ... in the low fat this is an amazing study in the low fat high carb group there was 20 fat in the medium fat medium carb groups there was 30 percent fat and in the high fat low carb group there was 40 fat ... the only thing they changed protein was the same remember all groups are isocaloric between men and women dietary fiber is the change is the same there's no changes”