The various nutrients required by the human body must be continuously supplied and supplemented through food. So, what exactly should one eat? This involves the proportional relationship of food, which is to establish a balanced relationship between the body's physiological needs and dietary nutrient supply, the concept of "dietary balance."
Amino Acid Balance
The nutritional value of food protein largely depends on the quantity and proportion of the eight essential amino acids it contains. Only when the quantity and proportion are close to the body's needs can human tissue proteins be synthesized; otherwise, the utilization of protein in food will be affected. The World Health Organization has proposed the proportions of the eight essential amino acids required by the human body. The closer the proportion is to this, the higher the physiological value. When the physiological value approaches 100, meaning 100% is absorbed, it is called complete amino acid balance.
Food Protein Amino Acid Composition Score: Human milk 100, egg 100, milk 95, soybean 74, rice 67, peanut 65, millet 63, wheat 53, sesame 50.
Proteins that can achieve complete amino acid balance are called complete proteins. This standard can be used to score the amino acids of proteins in various foods. The amino acid proportions in human milk and eggs are extremely close to those in the human body, so they can be called foods with balanced amino acids.
However, most foods have an unbalanced amino acid composition, which affects their nutritional value. For example, excessive leucine in corn affects the utilization of isoleucine; excessive arginine in millet affects the utilization of lysine. Therefore, in a diet that is primarily plant-based, attention should be paid to the rational combination of foods to coordinate the imbalance in amino acid composition proportions.
Energy Nutrient Composition Balance
Carbohydrates, fats, and proteins can all provide energy to the body, so they are called energy nutrients. When these three substances are consumed in appropriate amounts, their respective special functions can be exerted and they can mutually promote and protect each other. This situation is called energy nutrient composition balance.
The appropriate ratio of intake for carbohydrates, protein, and fat is 6.5:1:0.7. After physiological combustion in the body, they provide energy to the body as follows: carbohydrates account for 60%-70%, protein accounts for 10%-15%, and fat accounts for 20%-25%. This is called energy nutrient balance; otherwise, adverse consequences may occur.
When the carbohydrate intake in the diet is too high, the energy proportion will increase, disrupting the balance of the three, leading to obesity, and increasing the burden on the digestive system and kidneys, which will reduce the opportunity for intake of other nutrients; when the energy provided by fat in the diet is too high, it will cause obesity, hyperlipidemia, and heart disease; when the energy provided by protein is too high, it will affect the normal function of protein, cause protein consumption, and affect the nitrogen balance in the body. Conversely, when the energy supply from carbohydrates and fats is insufficient, the protective effect of protein will be weakened. The three are mutually influential; once an imbalance occurs, it will affect health.
Balance in Intake of Various Nutrients
The various nutrients we consume in our diet, over a certain period, should be kept within a range of no more than 10% deviation from the standard supply level. This proportion among them can be called the basic balance of nutrients.
Acid-Base Balance
Under normal circumstances, due to its own buffering effect, the pH value of serum is generally maintained between 7.3 and 7.4. Consuming appropriate amounts of acidic and alkaline foods will maintain the acid-base balance of body fluids, but if foods are improperly matched, it can cause physiological acid-base imbalance.
Common acidic foods include: egg yolk, rice, chicken, eel, flour, carp, pork, beef, dried squid, beer, peanuts, etc.
Common alkaline foods include: kelp, spinach, watermelon, radish, tea, banana, apple, strawberry, pumpkin, green beans, cucumber, lotus root, etc.
When foods are improperly matched and the amount of acidic food in the diet exceeds the required amount, it can lead to slightly acidic blood, darker blood color, and increased viscosity. In severe cases, it can also cause acidosis; at the same time, it will increase the consumption of calcium, magnesium, potassium and other dissociated ions in the body, causing calcium deficiency. This phenomenon is called an acidic constitution, which will affect health.