On the 2008 Beijing Olympic Games field, American swimming superstar Phelps was undoubtedly one of the most outstanding athletes, achieving the feat of winning eight gold medals in a single Olympic Games. In just a few days, he competed in eight events, with sometimes less than 20 minutes between two races. Many people are curious: why could the American "Flying Fish" Phelps, after finishing a swimming race, quickly move on to the next one, not only without exhaustion but also breaking world records one after another? Consuming carbohydrates 3-4 hours before exercise helps the body store glycogen and increase endurance.
As is well known, the energy consumption of water sports is six times that of land sports. Besides the athletes' own physical fitness and their usual training foundation, the rapid replenishment of energy in a short period is a strong guarantee for the "Flying Fish" Phelps to achieve his dream of eight gold medals, and his "secret" is to eat more carbohydrates.
To put it bluntly, this is the pasta and pancakes that foreigners often eat, and it is also the steamed buns, pancakes, noodles, and rice that Chinese people have been eating for thousands of years.
Linda, a member of the Tianjin Nutritionists Association, said that the protein content of pasta exceeds 15%, which is much higher than the protein content of flour in China, which is between 7% and 10%. Foreigners also like to eat it with tomato sauce, which is more nutritious. Lycopene in tomato sauce is a strong antioxidant that prevents cancer, fights aging, and has a good effect on men's prostate problems.
So why do carbohydrates have such powerful power? "Carbohydrates, which seem simple and unremarkable, include monosaccharides, disaccharides, oligosaccharides and polysaccharides. Monosaccharides are more easily absorbed and supplemented as blood sugar, and are converted into glycogen for storage in excess. They release energy during muscle exercise and long-term hunger, maintaining exercise endurance, thus ensuring the smooth progress of Phelps' high-intensity competitions and new breakthroughs in Olympic results," said Professor Cai Donglian, a professor in the Department of Nutrition at Changhai Hospital Affiliated to the Second Military Medical University.
From the perspective of daily exercise, 3-4 hours before high-intensity and long-duration exercise, supplementing a certain amount of carbohydrates, such as biscuits and snacks, can help the body store a certain amount of glycogen, thus avoiding the feeling of powerlessness and premature fatigue during the competition. Normal daily intake of rice and flour will not lead to obesity.
"Carbohydrates are the main source of energy for the body, and it is the most cost-effective source. They should account for 55% to 65% of the total daily energy, and the proportion for athletes can be a bit higher," said Lin Ning, a nutritionist in the nutrition department.
However, nowadays more and more people blame obesity on rice, flour and other carbohydrates, and even advocate a low-carbohydrate diet.
Deputy Chief Physician Fu Sanxian of the Nutrition Department of the First Affiliated Hospital of Zhengzhou University said that although carbohydrates have a high energy output, protein and fat also provide energy.
Usually, 1 gram of fat provides 9,000 calories, while 1 gram of protein and 1 gram of carbohydrates both provide 4,000 calories. From this, it can be seen that the increase in calories from consuming the same weight of carbohydrates is no more than that of protein and fat. Whether it will lead to weight gain depends on whether the total energy intake and total energy consumption are balanced.
"Normal daily intake of rice and flour will not lead to obesity. Most of the obesity in today's society comes from excessive consumption of fat and a significant reduction in the amount of exercise and activity," said Lin Ning. The 2007 Chinese Residents' Dietary Guidelines issued by the Chinese Nutrition Society has detailed regulations on this. The daily intake of grains, potatoes, and miscellaneous beans for each person should be 250-400g, and it is best to have 1/3 to 1/4 of them as coarse grains. Low carbohydrates and eating only "meat" to increase muscle mass increases the metabolic burden on the liver and kidneys.
In addition to the fear of obesity, the main reason why many parents ignore their children's staple food is that they put too much emphasis on protein intake, especially thinking that meat is rich in protein and can help children build muscle and increase strength.
Professor Cai Donglian said that if you try to increase muscle mass and lose weight simply by eating "meat", it is actually a waste. In the case of insufficient energy supply, that is, when carbohydrates are not consumed or are insufficiently consumed, protein will be used as an energy substrate to produce energy, which not only leads to "overkill" but also increases the metabolic burden on the liver and kidneys, and at the same time affects its "primary job" of repairing body tissues and maintaining renewal. "In addition, carbohydrates are metabolized and broken down into glucose, which is the essential energy for maintaining brain function," said Fu Sanxian. If the intake of carbohydrates is excessively restricted, when the blood sugar concentration drops, brain tissue is likely to lack energy, leading to impaired brain cell function, and causing dizziness, palpitations, and even hypoglycemic fainting.
Due to the mistaken belief that not eating staple food can help with weight loss, carbohydrate-rich grain foods have become a "thorn in the side" for some people.
In fact, in addition to providing carbohydrates, grain foods also provide other nutrients such as B vitamins, especially vitamin B1 and niacin, which are abundant only in grains.
Fu Sanxian said that a lack of vitamin B1 can easily lead to "beriberi" (different from athlete's foot), with adverse reactions such as irritability, forgetfulness, lack of concentration, suspicion, tenderness in calf muscles, palpitations, shortness of breath, low blood pressure, and edema. A lack of niacin can cause pellagra, where the exposed skin turns black and rough, in addition to neurological and gastrointestinal symptoms.