Please read this quite slowly
The word junk food appeared in the 1970's, to raise people's awareness of food that is considered to be unhealthy, although not every one agrees on exactly which food is junk food! The term is generally used to describe foods that are high in calories and low in nutrients.
Junk foods tend to contain large amount of fat, sugar and salt.
Junk foods also tend to be processed, which means they usually contain artificial flavourings and additives.
They're often packaged in boxes, cans or bags.
Some common examples of junk foods are sodas, or snack foods such as potato crisps, sweets.
Popular fast food items like hamburgers and chips are also often considered in the junk food category because they contain lots of calories but not many nutrients.
Thanks a lot for your help!