Fruits of any kind is not acid forming in the body. Nor is tomatoes which a lot of people seem to think it is!
Corn syrup which is rich in fructose is acid forming because its been stripped of the nutrients which the body needs to balance the ph level of the blood.
Oranges and Pineapples are definitely not acid forming. Its scientific fact. These foods are rich in alkaline forming chemicals. Or in layman's terms....Nutrients!
