By convention, in this context, the kilocalorie is written calorie. Protein and carbohydrates have about four calories per gram. Fat has about nine calories per gram. The daily number of calories needed depends on a person's age, size, physiological state, and level of physical exercise. Generally, men need more calories than women, and youngsters need more than older persons.
Nutritionists classify foods for a balanced diet in various categories.
Fats, oils, and sweets are considered extras to be used in very small amounts. Fruits and vegetables contain a variety of vitamins and minerals. Dairy products are rich sources of calcium, riboflavin, vitamin D, and protein. Children under the age of two should be offered whole milk, and children two to five years of age should be offered 2 percent milk. One-third of a cup of nuts or one egg can be substituted for the meat or legumes.