18. Deep-fried foods

A diet that includes large amounts of deep-fried foods is considered unhealthy and may negatively impact cognitive health over the years, as indicated by research conducted by the Italian Department of Public Health. 

Since they are high in unhealthy fats, deep-fried foods also have a negative impact on your cholesterol, heart, and liver. These foods are also more difficult to digest, potentially causing discomfort for some individuals.