Friends who have watched "The Promise" must be quite impressed by Jang Dongjian's line in the film: "Follow you and you will have meat to eat." Indeed, sufficient meat in the diet not only improves the quality of life, but also increases the body's energy from a physiological point of view and ensures the body's demand for protein intake.
Protein is a magical living substance in the body. Among the three major energy-yielding nutrients, the main function of sugar and fat is to provide energy for the body, while protein has a dual function: it can both It produces energy and can also provide raw materials for building tissues of the body. The growth and development of the body can be regarded as the continuous accumulation process of protein. Therefore it can be said that without protein there would be no life. Protein is composed of amino acids. In the body's protein metabolism, amino acids are mainly used for synthesis and catabolism. When the body is in a state of starvation, carbohydrate reserves decrease rapidly, and fat and protein are used as energy sources for long-term energy expenditure.
A man who loves meat will often include a large amount of meat products in his three meals a day. Especially with the increase in social meals after work, chicken, duck, and fish have become commonplace, and the protein intake in the meal is often sufficient. In today's society, with the popularization of health and nutrition knowledge and the emergence of an increasing number of "three highs" people in life, including the impact of fitness and muscle-building exercises on protein needs, people are increasingly aware that protein intake There should be a choice. Faced with numerous sources of protein in daily meals, how to more scientifically absorb high-quality protein on the basis of meeting the needs of the body has become an important part of daily meals. Which kind of meat to eat and how to eat it in a more scientific and healthy way have become the first questions that people who pursue health think about before using chopsticks. Before addressing these questions, let us first clarify how much protein our bodies need every day.
1. Dietary reference intake of protein
Protein intake includes two concepts: physiological requirement and supply. Physiological requirements refer to the amount of protein required to maintain life and ensure growth and development. The supply is to add a 50% to 200% safety factor to the required amount to eliminate individual differences and quality differences in nutrients in food, and maintain a high level of health and work ability. In 2000, among the recommended dietary nutrient intakes revised by the Chinese Nutrition Society, the recommended protein intakes (RNIs) for adult men and women were 75g/d and 60g/d respectively for light physical activity; respectively 80g/d and 80g/d for moderate physical activity. 70g/d; heavy physical activity is 90g/d and 80g/d respectively.
LuckWhether exercise increases protein requirements, research conclusions are not entirely consistent. For fitness people, protein intake should be 12-15% of total calories, which is about 1.2-2.0g/kg body weight. And it must not only meet the requirements in terms of quantity, but also in terms of quality, it should be at least 1/3 of high-quality protein with complete essential amino acids, mainly animal protein. Among them, soy protein is also a high-quality protein. Some people believe that eating more protein will promote muscle growth, but it turns out that an appropriate amount of protein must be combined with progressive strength training to achieve muscle growth. Eating too much protein will not lead to the synthesis of too much muscle. And excess protein is harmful from a medical perspective. It will increase the burden on the liver and kidneys; lead to increased fat storage; cause dehydration and acidification of body fluids, causing fatigue to occur earlier.
2. Reasonable choice of dietary protein
After clarifying the amount of protein our body needs to consume every day, what we have to do next is to reasonably choose foods to match the meal to meet the body's protein needs. There are many foods that can provide protein, such as casein and lactalbumin in milk, ovalbumin and lecithin in eggs, albumin and muscle protein in meat, soy protein in soybeans, and soy protein in wheat. Gluten, gluten in corn, etc. Therefore, in addition to meat products such as beef and mutton, eggs and dairy products, including grains such as rice and wheat, are ways for us to obtain protein. Since the amino acid composition of each food is different, in order to achieve an appropriate proportion of the body's essential amino acid types and quantities, we advocate the mixed intake of a variety of protein-containing foods so that the proteins in the food can complement each other and increase the biological function of the protein in the diet. value.
The quality of protein in food is also one of the basis for our choice of protein supplement. The ease with which the protein in food can be digested and utilized by the body varies from food to food. For example, the protein in oats is more difficult to digest than the protein in eggs. In general, since the amino acid composition of protein is relatively close to that of the human body, the amino acids in animal protein are the easiest to digest and absorb, and their utilization rate can reach more than 90%, followed by legume protein (about 80%), cereals and Other plant proteins are less efficiently absorbed and utilized. For men, whether it is to maintain health and maintain body energy or to meet the needs of bodybuilding and muscle building, animal proteins, such as meat, fish, eggs, and milk, are the best sources of protein in the diet.
1. Meat
The protein of meat mainly exists in lean meat, and fat in fat meat is mostly fat. Every 100 grams of lean pork contains 20.3 grams of protein and 6.2 grams of fat. Chicken meat contains 19.3 grams of protein and 9.4 grams of fat per 100 grams. The protein content of lean beef is equivalent to that of pork, with 20.2 grams of protein per 100 grams, but the fat content is only 2.3 grams. Protein and fat content per 100 grams of lean muttonThe amounts are 20.5 grams and 3.9 grams respectively. Therefore, from the perspective of limiting fat intake, lean beef and mutton should be chosen as the main meat to supplement protein. Arranging more than 7 ounces of lean beef in three meals a day can meet the protein needs of male white-collar workers who often sit in the office. Of course, if you are still doing bodybuilding and muscle-building exercises, the amount of protein you need every day will be higher. It is recommended that you use protein powder and other sports nutrition foods according to the amount of protein needed to grow muscles. While meeting your protein needs, avoid ingesting Too much fat is bad for your body.
After livestock and poultry are slaughtered, a series of biochemical reactions occur in the meat tissue under the action of enzymes, making the meat more elastic, and its edible value is highest at this time. Some people think that "eating meat is not as good as drinking soup." This understanding is also incomplete. During the cooking process, in addition to some water-soluble nutrients, part of the nitrogenous substances in the meat dissolve in the soup, making the soup delicious. However, after boiling, the protein in the meat will coagulate when exposed to heat, so most of the protein remains in the meat. , the protein dissolved in the soup is only a small part.
2. Eggs
Various poultry eggs have basically the same nutritional content, and eggs are the most commonly eaten. Eggs are the food with the highest absorption and utilization rate by the human body. The proteins in egg whites and egg yolks are both high-quality proteins. They contain 8 kinds of amino acids necessary for the human body, and the utilization rate can reach 99.7%. Eggs contain 13.3 grams of protein per 100 grams. In addition, eggs also contain a large amount of lecithin, calcium, phosphorus, iron and other elements and vitamins, so eggs have high nutritional value.
When eating eggs, be careful not to eat them raw, because the egg white of raw eggs contains some substances that affect the activity of B vitamins in eggs. In addition, the antitrypsin present in the protein of raw eggs will also affect the absorption of protein in the gastrointestinal tract and reduce the edible value of eggs. There are usually a large number of harmful bacteria on the surface of eggshells, and egg yolks and egg whites are easily contaminated by these harmful bacteria after the eggshells are damaged. Therefore, when eating eggs, be sure to cook them thoroughly before eating them. Generally, it is appropriate to eat 1 to 2 eggs a day. Excessive consumption will lead to excessive intake of cholesterol and protein, which will increase the burden on the liver, kidneys and other organs.
3. Dairy
The protein content of milk is also very rich. The protein content in cow's milk is higher than that of human milk. It contains 25 kinds of amino acids including 8 essential amino acids, mainly tyrosine, and its physiological value is second only to eggs. Milk available on the market includes raw milk, pasteurized milk, sterilized milk, etc. Raw milk has a short storage period, but is rich in nutrients and retains most of the active ingredients in milk.