Thanks for the heads up, since you've told me that all food is equal I'm going to switch my diet to only include Soda, Doritos and Hotpockets. I'm sure my body will adapt amazingly.
However, consider the trivial case of your calories coming from poison. Not shockingly, strict equivalence is out the door.
Which is not too say it is a worthless proxy. It is quite good, actually. But it is just a proxy.
Not to say this is a myth like Chinese Restaurant Syndrome, but there is honestly a lot of evidence either way so we can't make establish a causative relationship for everyone. It is quite possible for people to have a short term reaction to salt because the hormones in charge of water and sodium balance can take several days to stablise, but again, we are unsure of long term consequences especially on an individual level.
https://www.newscientist.com/article/2101015-does-eating-mor...
https://www.scientificamerican.com/article/its-time-to-end-t...
The rest of your symptoms suggest that you are either eating too much like the guy from Supersize Me, or have more underlying health issues that require a better designed diet to heal. It's not food but how you eat.
They are equal, as anybody with rudimentary knowledge of biochemistry can tell. Modern processed food have the added benefit of micronutrient fortification so your need of vitamins should be met mostly in case you actually plan to follow that diet.
The appeal of a "balanced and natural" diet has a mostly puritan origin but its benefits are far from clear. The only proven method to delay the onset of aging is caloric restriction. Kale and supplements are mostly placebo.
As I said in a sibling post, restricting calories works. But, so does restricting grams. The same way not writing code prevents bugs. It also prevents features, so is a somewhat worthless endeavor.