Obviously, junk food could be served as fast food

Fast food is served at a fast food restaurant, such as Mcdonalds, &c; while junk food a specific type of food such as chips, pop, &c.
Obviously, junk food could be served as fast food.
Essentially, the adjective: "fast" modifies the noun "food" in describing how long it takes the consumer to get the food ready to be eaten, that is the food will be ready very soon.
The adjective: "junk" describes the quality and nutritional value of the food. Here "junk" is considered as that which is not usable, i.e. garbage.
Therefore to answer your question, different aspects of the food are being described.
preparation time
quality
Fast food is served at a fast food restaurant, such as Mcdonalds, &c; while junk food a specific type of food such as chips, pop, &c.
Obviously, junk food could be served as fast food.
Essentially, the adjective: "fast" modifies the noun "food" in describing how long it takes the consumer to get the food ready to be eaten, that is the food will be ready very soon.
The adjective: "junk" describes the quality and nutritional value of the food. Here "junk" is considered as that which is not usable, i.e. garbage.
Therefore to answer your question, different aspects of the food are being described.
preparation time
quality
The clue’s in the name right?! It’s junk!
You’d think anything synonymous with trash, rubbish, or garbage wouldn’t be particularly appetising. But we love it.
Indeed, it accounts for almost 30% of the average American’s caloric intake.
To put it another way, 30% of the American diet is junk!
Key Advantages of Junk Food
It’s Tasty
It’s all sweet, salty, full of flavour and coated in delicious sauces
. Most people would go for the junk food every time. You only have to smell the bacon frying, the burgers grilling, and the pizzas cooking for the saliva to start flowing
2. It’s Quick and Easy
Junk food is also incredibly convenient
People are busy.
They’ve got responsibilities and commitments that take up time. We’re in a hurry, and need to get things done.
Consider lunch breaks
3. It’s Available 24/7
Likewise, junk food’s always available.
Junk food restaurants are everywhere, around every corner, and are open at all times.
Many of them literally never shut.
Key Disadvantages of Junk Food
1. It’s Unhealthy
Your heart suffers, your cholesterol suffers, your skin suffers, your energy-levels suffer, and so on. You’re more susceptible to serious health issues, such as diabetes, heart disease, and cancer. And more
2. It Contributes to Weight Gain
Obesity is rampant in the US.
Almost 45% of the country is obese. That’s not far off 1 in every 2 people who have it.
It’s scary, and junk food plays its part in that
It Impacts Mental Health Too
Physical health is only one part of the problem.
Junk food impacts the mental side of things too.
It does so in a number of ways. First off, there’s a direct link to physical and mental health. If your body feels good, then so does the mind; and vice versa
Hopefully,this post will help you make your mind up about whether junk food is not the best option.