Complex sentence: The idea that these diets can materially affect blood pH for the purpose of treating a range of diseases is not supported by scientific research and make incorrect assumptions about how alkaline diets function that are contrary to human physiology.
Split into simpler sentences: The idea that this diet can materially affect blood pH for the purpose of treating a range of diseases is incorrect. These claims are not supported by evidence and make incorrect assumptions about how alkaline diets function that are contrary to human physiology.