High fat diets boost endotoxin absorption and catecholamines. It's also very difficult to eat high fat without getting too much unsaturated fat, which accumulates over time causing inflammation and aging. High protein diets boost catecholamines.

The long standing conventional wisdom that you want to be a sugar/carb burner is correct. Your cells function best on a steadily available supply of glucose backed with plenty of glycogen. Fructose is protective against stress, so a decent amount of sucrose is desirable.