Do you live on caffeine because you are always tired? Are you chronically inflamed or in pain? Have a few extra pounds that love you so much they refuse to leave?
What we eat literally becomes the building blocks for all the cells in our bodies. That is the importance of what we eat. It is really that simple. (nothing about our bodies is simple)
Some cells replace themselves quickly, others not so quick. For instance, your skin cells replace themselves approximately every 6 weeks, red blood cells every 4 months, liver cells replace themselves every 300 - 500 days, bone and fat cells every 10 years. I'm oversimplifying things to make a point. What you consume has the potential of long term consequences. If I'm so busy that I don't have time to cook and I make it a habit to stop at a drive-thru for lunch/dinner often then the longer I do that then my cells are being created by those building blocks. Not enough vitamins and minerals create poorly constructed cells which you will be fighting against.
Variety in what you eat not only fights boredom it also provides the essential fiber, protein, vitamins, and minerals the body needs to work in its most efficient manner.
The moral of the story, don't eat nothing but garbage unless you are ok feeling like garbage!