Scientific Weight Loss Diet Guide: How to Control Weight Through Nutritional Balance?

Nutritional Composition of Food: Every food has different calorie content and nutritional components. For example, grains are high in calories but lack minerals and vitamins, while vegetables and fruits are low in calories but provide abundant vitamins and minerals. Therefore, a diet plan must balance both, providing sufficient energy and essential nutrients. Otherwise, nutritional supplements may be necessary to compensate for the deficiencies in food. For example, people who cannot consume milk or dairy products may have insufficient calcium intake and can supplement with calcium-rich foods to meet their needs. Daily recommended intakes of nutrients and various food nutrition tables can be used to plan daily meals, also known as scientific dietary planning.

Nutritional imbalances can lead to illness. For example, a deficiency in vitamin A can cause dry eyes, keratomalacia, or night blindness; a deficiency in vitamin C can cause scurvy and bleeding; a deficiency in vitamin D can cause rickets and osteomalacia; and a deficiency in calcium can cause osteoporosis.

Nutritional imbalances can lead to illness. The three major nutrients, inorganic salts, trace elements, vitamins, and fiber.

Carbohydrates (sugars): 1g carbohydrate = 16.7kJ (4kcal)
Carbohydrates are one of the three major nutrients. After being digested, sugars in food are converted into glucose and absorbed, passing through the bloodstream. Some glycogen is stored in the liver and muscles. The amount of glycogen stored in the liver is small, but it helps maintain stable blood sugar levels. Muscle glycogen, mainly in skeletal muscle, is readily available to the body. A smaller portion of glycogen is stored in body tissues and cells.

The body's functions require frequent intake of glucose from the blood to meet metabolic needs. The liver can also synthesize some glycogen through gluconeogenesis using lactic acid, pyruvate, glycerol, and certain amino acids (non-carbohydrate substances). Liver glycogen will be completely depleted within ten to fifteen hours if not replenished.

If sugar intake exceeds the body's consumption, the excess sugar is converted into fat (triglycerides) and stored in the body, leading to obesity.

Foods containing carbohydrates mainly include rice, wheat, and various tubers.

Protein:
1g protein = 16.7kJ (4kcal) of energy, the same as carbohydrates.

Protein is one of the three major nutrients and a major component of human tissues and organs, essential for life. Dietary protein is digested in the gastrointestinal tract into amino acids, which are then absorbed into the bloodstream via the small intestine.

Protein exists in various foods and can be divided into two main categories: animal protein and plant protein.

Based on the composition of essential amino acids, proteins are classified into the following three categories:

(1) Complete Proteins: Contain a wide variety of amino acids in sufficient quantities and appropriate proportions. They are essential for maintaining human health and children's growth. Examples include casein and lactalbumin in milk, ovalbumin and lecithin in eggs, albumin and myoprotein in meat, soy protein in soybeans, glutenin in wheat, and glutenin in corn.

(2) Semi-Complete Proteins: Contain a complete range of amino acids, but in small quantities and in inappropriate proportions. (2) Proteins that can sustain life but do not promote growth, such as gliadin in wheat.

(3) Incomplete proteins: These contain amino acids that are incomplete in both type and quantity, and therefore cannot sustain life or promote growth and development. Examples include gelatin in animal skin, zein in corn, and pea globulin in peas.