Diet
General information relating to diet.
I firmly believe that diet is the main contributing factor to health. Disease does not cause itself, but rather, living in a way unintended by nature does.
We evolved to survive in the wild. It would make no sense for any living thing to become diseased or overweight (not the weight some animals gain for winter, but unnatural, unhealthy weight that impedes an animal's ability to survive) as that would go against the natural order, it would not be consistent with evolution and survival of a species.
It is when an animal, human or otherwise, is exposed to toxins and/or malnourished that problems appear. We are exposed to toxins in the air and other external sources. We are also, and more much more directly, exposed to toxins through diet. When you put things into your body you are directly exposing yourself to it and are much more vulnerable. Your body has to deal with those toxins and this takes away to varying degrees it's ability to deal with the toxins you are exposed to through the air and your skin. This leaves you more vulnerable. This doesn't even take into consideration depriving your body of things it needs to function optimally!
Surely you can see why diet is so important to our health. There is a cause and effect relationship between what we put into our bodies and what our bodies give back to us. Health begins from the inside out.