Simply speaking everything in nature is chemistry (0 - 14 pH) and your blood is 7.35 -7.45 pH. Everything you breathe, ingest, and put on your skin has its unique pH level depending on its chemical make up of minerals (alkaline minerals include magnesium, calcium, potassium, boron etc). So, these go into your body and neutralise acidic toxins in the body.
But the body needs to keep its pH quite stable to function properly so it has mechanisms it uses to always remain within those boundaries such as producing sodium bicarbonate (in the kidneys, pancreas and stomach), pulling calcium from your bones, producing cholesterol as well as holding onto water (edema) - these are all symptoms the body uses to continually keep a slightly alkaline state.
BUT if you are eating and drinking acidic things like coca cola for example (I think it's around 3 pH which is roughly 10,000 times more acidic than your blood) then the body needs to work out a way to balance its chemistry. And the body can only work so hard for so long until it starts to breakdown and wear out causing dis-harmony and dis-ease.
So, the body never really BECOMES more alkaline, because the blood is already alkaline and needs to remain that way within its tight band but you can either make it easy for the body remain in the band or you can make it hard for the body to remain in that band – its your choice.
For the human body to function optimally, the internal environment needs to be relatively alkaline. When too much waste builds up inside the body in various areas, the body can start to become acidic. This is the reason why most natural alternatives to treating cancers involve high alkaline diets to detoxify and bring more oxygen to cancer sites.
The more acidic the body becomes (the harder it has to work to remain ‘in the green’), the less vitality it can experience.