Nutrition Nutrition is the process of eating, absorbing and using the nutrients the body needs for growth, development and maintenance of life.
People need to eat a healthy diet, consisting of a variety of nutrients - substances found in foods that nourish the body, in order to obtain adequate, appropriate nutrition. A healthy diet enables people to maintain the desired weight and body composition (the percentage of fat and muscle in the body) and carry out their daily physical and mental activities.
Eating too much can lead to obesity. Intake of large amounts of some nutrient, vitamins or minerals, usually has harmful (toxic) effects. In addition, not eating enough nutrients can lead to nutritional deficiencies, leading to nutritional deficiency disorder.
Assessment of nutritional status
Doctors ask people about their eating and diet habits and conduct a physical examination to assess body composition and function to determine whether they are consuming the right amount of the nutrient.
Height and weight are measured, BMI is calculated. Body mass index is calculated by dividing weight (in kilograms) by the square of height (in meters). A body mass index is considered normal for men and women if it ranges between 19 and 24. In the United States and other developed countries, the body mass index is higher than 24 for many people.
Body composition, including the percentage of fat in the body, is sometimes estimated by measuring the thickness of skin folds or performing an electrobiological impedance analysis. More accurate methods of determining this ratio include the weight of people underwater (hydrostatic weight) and dual-energy x-ray absorptiometry (DXA) scanning, but these methods are not easy to apply, may be expensive, and are not readily available. Always . It is mainly used in research.
Sometimes levels of many nutrients in blood and tissues can be measured. For example, measuring the level of albumin, which is the main protein in the blood, may help determine whether people are deficient. Nutrient levels drop when nutrition is insufficient.
Skinny versus chubby: body composition
Maintaining an appropriate weight is essential for both physical and mental health. The standard height and weight table can be used as a guide. However, BMI is the most reliable.
A less straightforward but necessary examination is to find out the proportions of muscle and fat in the body (body composition). There are several methods for determining body composition:
Hydrostatic weighing: Weigh people underwater in a small pond. Bones and muscles are denser than water, so people who have a high percentage of lean tissue have more weight in water, while people who have higher fat have less weight.
Although this method is considered the most accurate, it requires special equipment that is not readily available, as well as the length of the procedure and the great experience required to perform it.
The thickness of skin folds: the body composition can be estimated by measuring the amount of fat under the skin (the thickness of the skin).
A skin fold in the back of the left upper arm (the triceps skin fold) is pulled away from the arm and measured with a caliper. The skin fold is considered normal if it is about 1.25 cm in men and 2.5 cm in women. This measurement can be used in combination with the circumference of the upper left arm to estimate the amount of skeletal muscle in the body (lean body mass).
Biological Impedance Analysis: This test measures the resistance of body tissues to an undetectable low-voltage electrical current.
People should stand barefoot on metal footplates, and an electric current is sent up one foot and the bottom of the other. Body fats and bones are much more resistant to the transmission of electrical current than muscle tissue. Doctors can estimate the percentage of body fat by measuring the resistance to electrical current. This test only takes about one minute.
Dual-energy x-ray absorptiometry (DXA): This imaging procedure accurately determines the amount and distribution of fat in the body. Dual-energy x-ray absorptiometry uses a safe and extremely low dose of radiation. However, it is too expensive to perform routinely.
Ingredients of the diet
Feeders are generally divided into two categories:
Macronutrients: It is required to eat large amounts of macronutrients daily. It includes proteins, fats, carbohydrates, some minerals, and water.
Micronutrients: Take small amounts of micronutrients daily - in milligrams (thousand grams) to micrograms (million grams). They contain vitamins and some minerals that enable the body to use the macronutrients. These minerals are called trace minerals because the body needs very small amounts of them.
It is necessary to drink 1 milliliter of water for every calorie of energy consumed, or about 2.5 liters per day. The body's need for water can be met through natural water that is found in many foods, drinking fruit or vegetable juices, caffeine-free coffee or tea, as well as water. While drinking alcoholic beverages, caffeinated coffee and tea, and soft drinks may increase urination, they are less helpful.
The foods consumed in the daily diet contain up to 100,000 substances. But only 300 of them are classified as nutrients, and only 45 are classified as essential nutrients:
Vitamins
Minerals
Some amino acids (protein components)
Certain fatty acids (fatty acids)
Essential nutrients cannot be manufactured by the body and must be obtained from the diet.
Foods containing many other beneficial ingredients, including fiber (such as cellulose, pectins, and mucilages).
Foods also contain additives (such as preservatives, emulsifiers, antioxidants, and stabilizers) that improve food production, processing, storage, and packaging.
