Caporegime
Reading it a bit deeper, it quire clearly states:
So low carb, and getting the majority of your protein and fats from plants improved mortality compared to even the mid-range carb diet that includes meat.
In the ARIC cohort and in meta-analysis, increased consumption of animal-based protein and fat instead of carbohydrate was associated with a significant increase in all-cause mortality (p<0·0001; table 3). Alternatively, increased consumption of plant-based protein and fat instead of carbohydrate was associated with a significant decrease in all-cause mortality
However, in our analysis, when carbohydrate is substituted for higher animal fat or protein intake it is associated with both higher cardiovascular and non-cardiovascular death, whereas plant-based substitutions are associated with both lower cardiovascular and non-cardiovascular death, indicating that food source could be an important consideration for both causes of mortality.
So low carb, and getting the majority of your protein and fats from plants improved mortality compared to even the mid-range carb diet that includes meat.