You are what you eat. The trick is learning to "listen" to your body. It will tell you loud and clear whether the food you are considering to consume will upset it or please it. It is a matter of pausing for a moment, clearing the mind, focusing on the food and then shifting the focus to how your body feels. It will without fail let you know.
The problems start when we listen to our thoughts, our internal dialogue. Our diet is often moved by habit... habit of thought that is, which then sets up habit of emotion, which feeds back to our thoughts... and so the vicious circle goes.
Break with thought and go with what the stomach feels.
Yes, I've been working on doing exactly that. It's very enlightening.
Yes, I'm now at a point, where I look at even packaging and feel if my body is going to be happy with digesting said "food".
Tip : level up by delving into the medicinal and culinary uses of herbs. When you do have an imbalance, for what ever reason, the power and range of options that herbs present are amazing. When you learn to recognise the plants, you will discover the natural pharmacy around you.