The main component of a healthy and balanced diet is in the parity of consumed nutrients and subsequent use of energy with the background of individual specifics and genetically predispositions (Grosvenor and Smolin, 2012, p.35).
Although the general guide is that a healthy diet is on balance of all food types, placing the main emphasis on vegetables, fruits, and only then on grains and proteins; but this also means that it is not enough simply to have a balance of fruits, grains, vegetables and proteins in equal measures, the assessment of individual necessity of particular nutrients is crucial for a healthy diet (Grosvenor and Smolin, 2012, p.33).
Therefore, the main components of a balanced diet would be a balanced intake of nutrients relevant for specific physiology. In other words, this means that people with obesity, metabolism problems and potential heart diseases will have to limit the intake of calories from fat, grains and sugar-containing products to levels below the advised average (Grosvenor and Smolin, 2012, p. 40). Another component of a healthy diet is in reduction of unexpected sources of sugar, like fizzy drinks, soda waters, chocolate bars, snacks and fast foods. This aspect is important because, it is often forgotten that a can of coca-cola also has sugar which gets into blood even faster than chocolate consumption due to its fizzy nature.
In this context, it is advised "to limit calories from solid fats and added sugars to 260 Calories a day" (Grosvenor and Smolin, 2012, p. 45). The same is the reason for limiting sodium intake to 2300 mg a day (Grosvenor and Smolin, 2012, p. 45). The next component is to eat more of fresh fruits and unprocessed products. In grains, it is advised to prefer whole grains since they are better for digestion (Grosvenor and Smolin, 2012, p. 45).
Drinks-wise, it is preferable to drink at least 2 litres of water, and not to substitute it with tea and coffee, or even fruit juices because fresh, still water has entirely different roles digestion (Grosvenor and Smolin, 2012, p. 38). From all mentioned above, it can be concluded that irrespective of existence of general rules, a healthy diet is an individual matter and should be individual-oriented and developed for each person's nutritional and life-style requirements.
Reference
Grosvenor, M.B. and Smolin L.A. (2012). Visualizing nutrition. New York: John Wiles &
Sons.