In nutrition, the diet is the balance of food ingested by an organism or individual. The diet must contain the essential substances that an organism needs to survive and to perform its normal functions. It should also control the environment around it, including the energy available to the organisms and the pH environment of the system. Without a balanced diet, an organism cannot function well.
Most people gain weight during their teenage years because they consume more calories and fat than what they should for their height and age. Because they gain weight so quickly, they usually undervalue the importance of a balanced diet. Teenagers have a special need for micronutrients because their metabolisms are not fully developed. micronutrients can be found in vegetables, fruits, and whole grains; meats, fish, and poultry; dairy products; wheat products; and fat-free or low-fat products. A diet rich in nutrients is important to adolescents for the development of their bodies and their self-image.
Various diets are recommended for people with varying appetites. Many vegetarians and most health-conscious people eat eggs for breakfast. Low-carb breakfast eggs, or summary eggs, are high in protein and the B vitamins. Skim milk, cheese, and cottage cheese are good sources of calcium. Other foods that meet these requirements are green vegetables (especially spinach and broccoli), tomatoes, and low-fat or skim milk.
Diets that are rich in sodium (salt) are usually followed by those with high blood pressure. People with high blood pressure are advised to limit the amount of sodium they take in by at least 100 milligrams each day. Saturated fats are also bad for the heart and are usually found in fatty meats, butter, processed meats, and canned fish. Oily fish, such as swordfish, trout, and tilefish, is good for reducing high blood pressure, but many people also like to eat oily fish.
Some diet plans recommend restricting the amount of calories one eats during the day while others recommend increasing the amount of calories taken in. The American Dietary Association cautions against diets that reduce intake of calories. The amounts of calories vary depending on body size, age, sex, height, and overall health. Some of the major food groups and their respective contribution to daily calorie intake include: protein, fats, carbohydrates, fiber, fruits, vegetables, dairy products, fats, and salt.
Low-calorie and low-fat dairy foods are good for promoting weight loss, and some diet plans do recommend a certain level of dairy foods in a diet. One group of substances that the American Heart Association recommends against is cholesterol-rich foods (cholesterol-containing dairy foods). The FDA advises dieters to get their daily calcium from low-fat yogurt, and to choose calcium from sweetened yogurt if possible. The FDA does not recommend taking vitamin or iron supplements.