The alkaline diet may support health by limiting processed foods and promoting more whole foods. However, it doesn’t help fight disease by affecting your body’s pH levels. The alkaline diet is based on the idea that replacing acid-forming foods with alkaline foods can improve your health. Proponents of this diet even claim that it can help fight serious diseases like cancer. However, scientific research does not support this. The pH levels in the body vary greatly in different parts, with stomach acid being highly acidic and blood slightly alkaline. Diet usually doesn’t significantly alter the pH of your blood but may affect the pH of your urine. Osteoporosis, a bone disease, is not directly related to the acid load from diet. A high protein diet may even benefit bone health. Overall, the health benefits of the alkaline diet come from its emphasis on whole and unprocessed foods, not from changing your body's pH levels.