Saturated fats, such as butter, should be eliminated. Monounsaturated and polyunsaturated fats, such as sunflower oil, safflower oil, corn oil, and olive oil, are better fats and tend to lower the HDL's in your blood, and thus help you prevent coronary artery disease. Eating well is not complicated but good nutrition does require you to take the nutrients in the proper balance. Insufficient iron can cause a zinc deficiency. Excess zinc can cause a calcium deficiency.
Excess salt can cause a negative calcium balance.
Everyone agrees that you should eat a variety of good fresh foods that provide the six classes of nutrients necessary for health. It is also an established fact that nutritional balance is of paramount importance for good nutrition. However, the precise determination of what constitutes nutritional balance has been the subject of much debate. I have provided two food pyramids. Both approaches to good nutrition should be studied carefully.