What would be a good way to prevent communicable disease such as a common cold?

Can someone give me one specific health problem (within unhealthy eating) and explain it. !

Example of health promoting behavior

Diseases may arise when proteins fail to fold correctly in their last stages of processing and/or are directed towards the lysosome rather than towards the cell membrane. cystic fibrosis is an example of this type of disease. in cystic fibrosis, a functional ion channel is sent to the lysosome for destruction rather than being sent to the plasma membrane. given this observation, the cellular component that is most likely the cause of the disease is the