The body’s most basic need is for energy. The energy in food is measure in units call kilocalories (commonly shortene to “calories”).
One kilocalorie is the amount of heat energy need to raise the temperature of 1 kilogram (2.2 pounds) of water 1° C (1.8° F). (More precisely, it is the energy required to raise. That water from 14.5° C to 15.5° C at one atmosphere of pressure.)
Three major types of nutrients supply the body with energy, or calories: carbohydrates, proteins, and fats. One gram (0.035 ounce) of either carbohydrate or protein provides four calories. Fat is a more-concentrated source of energy, with each gram providing nine calories. Water, vitamins, and minerals supply no energy in and of themselves, though the body uses many of them in energy-releasing processes.
The body needs the energy in food to do everything from blinking eye to running a race.
It also needs energy to perform such essential functions as breathing, maintaining body temperature, growing new cells, and even digesting food. The total number of calories needed each day depends on many factors, including a person’s age, sex, weight, and especially level of activity. For example, a woman who weighs about 120 pounds (55 kilograms) might expend 1,850 calories on a day when she is fairly sedentary but may use more than 3,000 calories on a very active day.
If a person takes in more food than is require to meet the body’s need. The excess calories eventually converted to fat a form of stored energy found mostly within adipose tissue. That causes weight gain. Eating too little causes weight loss over time. Because the body must use stored fat for energy. One pound (0.5 kilogram) of adipose tissue is equal to about 3,500 calories.
Maintaining a healthy weight is a สมัคร ufabet balancing act. Food provides energy, and physical activity uses up energy. If weight loss is advisable, experts recommend both reducing one’s daily calorie intake and getting more exercise.
Nutrients
The nutrients divide into six major types: carbohydrates, proteins, fats, vitamins, minerals, and water. Each nutrient performs specific functions to keep the body healthy. All the nutrients work together to contribute to good health.