Any dish can rank from nutritionally decent to junk

Ok, so in what way "dal" can be prepared to call it junk food?

We often confuse fast food with Junk food.

I personally consider a food as junk, if it goes through the synthetic process of preparation and/or use of ingredients; could be lack of nutritional benefits, high in fat, trans fat, saturated fat, etc. By and large, the processed food.

What we consider 'junk' is traditional to others and vice versa.

Could be.... but only one-way...junk food can be traditional to some people, but traditional food may not necessarily be junk food. So the vice versa is not true if the traditional food like "plain rice-dal" can ever be prepared in any way to classify it as junk food. In what way "idli" can ever be made to classify it as junk food. Put simply, there are some traditional dishes in India which has raised the bar of "healthy regime" so high that, you can not ever make it a junk food by altering/adjusting the preparation. I agree that depending upon the preparation there would be a different distinction, that distinction could be spicy food, but again a spicy food may not necessarily be junk food.

People often confuse fast food with junk food, because most of the fast foods are junk food, although not all.