Its fairly impossible to provide hard evidence that low carb high fat is inherently better because anyone who looks at the studies will instantly point out one of a couple confounders: 1. the LCHF diet eliminates wheat or other allergens 2. the LCHF has a higher protein content 3. the LCHF has a more nutrient dense profile. There is some interesting stuff that I have read regarding carbohydrate full oxidation requiring more complex I activity which would ultimately lead to more ROS production by the mitochondria. Oxidative stress is basically the factor in aging and metabolic disease. Does this pan out beyond biochem though? Dunno. Have to wait for more studies or till someone points them out I suppose.
"Therefore shifting away from glucose utilization toward lipid and amino acid utilization would be expected to substantially reduce the production of reactive oxygen species, without necessarily reducing ATP production. As described below, other beneficial effects also occur as a result of this altered pattern of glucose fuel use, including a shift toward producing antioxidizing NADPH and increased protein and lipid turnover, which reduces the accumulation of oxidized protein and lipids.
Jeff Volek recently did allude to some unpublished research about the antioxidative properties of a VLC diet and its implications in better recovery from exercise. Hopefully it hits the wire soon to have a look at.