Nutrition

             Nutrition.
             The study of nutrition involves everything that the body does.
             with food in order to live, like function, and grow. Foods that are eaten regularly make a diet. Although were you live and how you eat play a major part in your dietary habits, food choices vary from person to person. What people eat affects their health and how they live. Plants make their own food from, water, and air. People can't make their own food but eat plants, and meats to survive. The body's most important need is for energy. To get energy it needs food as a fuel and oxygen to burn it. The amount of energy food produces is called calories. A food calorie, is the amount of heat required to raise the temperature of (2.2 pounds) of water 1 degree Celsius (1.8 degrees Fahrenheit).
             The body changes the calories in food into energy, which is very nesscary for the little things like blinking an eye to running a race. Energy is also used for the growing process, for rebuilding damaged cells, and for regulating the body. The number of calories needed each day depends on how much energy your body uses. An active kid can need more calories than an adult who works at a desk. The body needs more calories in cold weather to stay at an even temperature.
             If a person consumes more food than required to meet the body's needs, the extra calories become fat . That causes weight gain. Eating too little causes weight loss because the fat is used for energy. One pound of stored fat has almost 3,500 calories. If weight loss is desirable, the best way to lose weight is by eating less of high-calorie foods and getting more exercise.Usually for most people a safe limit for losing weight is 2 pounds a week. Quick and easy weight-loss diets are fads ;because most are unbalanced, puting emphasis on one kind of food and excludeing others. To function, humans must have nutrients.