Nutritional balance is a determining factor in healthy eating, or rather, only by eating healthy eating is it possible to maintain the nutritional balance.
Nutritional balance is a parameter that assesses the amount and proportions of individual nutrients and nutritional components taken from the diet. Each of them has a very specific function, which is why over the years it has been attempted to determine its actual needs.
An organism that does not benefit from a balanced diet has greater difficulty in maintaining the so-called homeostasis. Obviously, being an almost perfect machine, as far as nutrition is concerned, the physicist makes use of an excellent autonomy; this means that it is tendentially designed in order to “survive” under any circumstance.
Ultimately, healthy eating guarantees the maintenance of physical balance and sometimes also contributes to psychic balance.
Now, the question that arises spontaneously is: What principles of nutritional balance subordinates the definition of healthy eating?
It is difficult to respond clearly in a few lines, also because the needs are subjective and vary (but not always as much as you can believe) according to age, sex, lifestyle and subjective components such as the size of the skeleton and musculature, metabolic predispositions, hereditary diseases etc..
Since nutrients and nutritional components are really many and all fundamental, you need to stay on the generic.