The idea of body alkalinity is nonsense. The normal arterial blood pH range is between 7.36 and 7.44. The normal human stomach has a pH which can range from approximately 1 to 3 but is usually closer to 2. If by some miracle you manage to fuck with your blood pH, you'll be dead in an hour. If you "alkalyse" your stomach acid (a contradiction in terms) you won't digest anything and you'll kill the barrier of protection against viruses etc. that we consume with every bite.

YES choice of the food we eat is really important, as is fasting. NO it doesn't "alkalyse" any part of the body. The terminology is wrong.