5. Too much citrus fruits
In the Caribbean. we have an abundance of citrus fruits, however consuming an excess amount of it can mean too much ascorbic and citric acid, or too much acidity, in the stomach. The kidney therefore has to do more work. Variety is the key here. You can have a variety of juices and fruit juices, not just grapefruit or orange everyday. Also, remember that too much citrus fruit juices can cause boils and pimples. This is because the kidneys can't take care of the excess juices in the skin and the kidneys in one moment. However, citrus fruit and its juices are useful in hot climates, a lot more than in cold climates.
Do remember: One orange a day will give you 93% of all the vitamin C you need. Let that be your guide.