What we eat does affect our health. After all, when God made these bodies, He also made food to keep them running. Altering that food, such as turning whole wheat into white bleached flour is not providing the body with the nutrients that our foods were created to provide. When we use artificial flavors and colorings, the body has to defend itself against the chemicals that weren't meant to be considered food. Excess acidity is known to be associated with arthritis.
Balance is the key.
When the body is over-acidic, it doesn't mean that we need to eat only alkaline foods. Some try to avoid all acid foods and then shortly thereafter drop the whole idea since it is too big a lifestyle change for one day. There is also a link to plants of the nightshade family. Vegetables are vital. Researchers credit eliminating meat fat, but also suspect fruits and vegetables having undefined benefits.