I mean a healthy diet is a variety of fruits and vegetables, with a decent supplement of whole grains and occasional lean meats and eggs. Minimally processed as much as possible - whole ingredients should be the majority of calories.

The details don’t matter so much, as long as you get a variety and generally stick to the above guidelines.

I think you can judge how healthy a diet is by how many people get diseases, malnutrition or premature death as a result of a diet, and almost nobody is going to suffer because of that diet plan above.