"Ailments" are oftentimes simply caused by an extreme intolerance to wheat and other grains, or dairy. It is ridiculous how many people don't qualify as celiac or lactose/casein intolerant but are still harmed by them. Muscle mass counts as weight too! And it is apparent that when you isolate one macronutrient you control insulin resistance, even if it is carbs. But the fact of the matter is that to be optimally healthy and age optimally you need a good chunk of fat and protein, and especially ruminant fat, brains, game meat, fish, and the like. Watch raw vegans get sick to their stomachs the second they eat anything but what they do.
Stabbing conventional wisdom in its face.
Anyone who wants to talk nutrition should PM me!