People should follow the food pyramid and eat a wide variety of food and also from a variety of food groups, including carbohydrates, proteins, fats, vitamins, minerals and adequate amounts of water, in order to stay fit, healthy, and also to provide their bodies with the requisite nutrients.
Basically, there are two types of nutrients -- micronutrients (including vitamins, minerals, and phytochemicals) and macronutrients (including carbohydrates, proteins, fats, amino acids and water).
Vitamins And Minerals In Foods
The micronutrients are needed in relatively small amounts in comparison to the macronutrients. While they are very important for the healthy functioning and growth of the body, micronutrients do not contain any energy but macronutrients do contribute a significant amount of energy to the body when digested. The body simplifies nutrients through digestion in order to utilize them. Macronutrients are digested to release energy but only when there are sufficient micronutrients to facilitate release of these nutrients for breakdown. Therefore, both micronutrients as well as macro nutrients are important for the body.
Not all the micronutrients and macronutrients present in our diet are completely absorbed by our body. Although the body uses carbohydrates as its main source of energy, it also uses up proteins and fats at times of carbohydrate unavailability. This is the reason why the general thumb rule has been framed which says that 50 percent of the body's energy requirements must be sourced from carbohydrates, 35 percent from fats and 15 percent from proteins. However, the fact remains that of the energy containing macronutrients, fats provide the most energy by weight to the body. This is because while one gram of carbohydrates and proteins provide just 4 calories, the same quantity of fat (one gram of fat) provides 9 grams of calories to the body.