Chest mucus lines the walls of your respiratory system. This mucus contains antiseptic enzymes that help protect you against infections, bronchial blockage and congestion. When we become ill, this chest mucus (phlegm) is produced in larger amounts and immunoglobulins work to fight invading or foreign bodies. This mucus attaches itself to the virus or bacteria, and is expelled when you cough. Excessive mucus is usually caused by infections such as bronchitis, the flu and pneumonia. If you are experiencing an increase of mucus, there are several foods you should avoid.
Dairy products contain protein molecules called "casein" that are known to cause mucus secretions. Casein can be very hard to digest. When you are producing large amounts of mucus, try to avoid products such as milk, butter, cheese, cottage cheese, cream and yoghurt, as they are the most mucus-creating foods in the human diet. Dairy products also contain a sugar called lactose that creates mucus as well, according to health site Detox.net.
Meats that come from animal flesh can produce excess mucus in the chest, almost as much as dairy products. It is a good idea to avoid meat, fish, eggs and fowl products when you're sick. Meat products cause less respiratory distress than dairy products, since they lack the lactose found in milk.
Consuming too much soy can cause more chest mucus than any other food derived from plants. Trading meats and dairy for soy can cause unhealthy mucus to build up in your chest and body. Try to use soy sparingly if you are already sick by avoiding foods such as tofu, soybeans and tempeh until you are feeling better.