Food is subjective. Therefore food is just food. We cannot prove good and bad when it comes to anything, much less nutrition. You see, everything is relative to the individual and their personal preference, beliefs and experience around food. So why is it that almost everywhere we go we see food being labeled this way?
Humans love certainty. We hate not knowing the "truth". Having a list of good foods and a list of bad food creates certainty so that decisions become a lot easier to make.
It's Easy to Prescribe
It's a lot easier to give you a simple order of "do this it's good for you" or "don't do this it's bad for you". Labeling food allows for easy instruction which leads to higher compliance and less overwhelming thoughts.
So what's the problem?
Think of 3 foods you like off of the top of your head that you know in the back of your mind aren't the healthiest for you, but you really enjoy eating them. Now, imagine being told that they are bad for you... and that you will never get to where you want to get to physically unless you give them up for good.
You feel demoralized, a bit angry and probably don't feel like it's possible to achieve your goals.
But you tough it out (for the short term) and cut out all of the bad foods. You lose weight, feel better but at the same time, feel a bit deprived. Before you know it you are unable to cut out these "bad" foods any longer and are right back to where you started.
When somebody tells us we can't have something we end up wanting it more.
Labeling foods allows people trying to help other people with their health and fitness create certainty and higher compliance, but at the same time it entrenches a belief about food in a client's mind. And that belief ends up back firing and stunting long-term permanent change in a client's progress.
See food for what is really is. Food. Objects. Look at each food in a way where you separate out all of the bias and dogma and see only the facts. This food came from X. This food has X artificial sweetener in it. This food has X amount of protein in it. Gather information and create your own certainty around food based on if it serves you.