Is food better eaten raw or cooked?
The meaning of cooking: sterilization, softening, helping digestion and absorption.
From raw food to cooked food, it was once considered a great historical progress, accompanied by a great extension of human life. Why do you want to heat and cook? Can't you digest and absorb raw food?
Indeed, many foods can be digested and absorbed without heating, including raw meat, raw fish, raw vegetables and fruits.
Fish and seafood are both animal foods, and animal cells have no cell walls, so they can be digested and absorbed when eaten raw and cooked. People want to heat cooked fish and seafood for two main purposes: one is to kill microorganisms and ensure food safety; The second is to harmonize the flavor, enrich the taste and create delicious food.
Of course, cooked fish will be easier to digest than raw fish. This is because after heating, protein denatures moderately and loses its three-dimensional structure, which is more conducive to the attack and decomposition of protease in human stomach. Studies on animals have also proved that cooked food can reduce the energy consumed by animals to digest and absorb food. Therefore, for some people with weak constitution, it may be more appropriate to use meat as cooked food.
Vegetables are plant-based foods. They have tough cell walls and are rich in fiber, which can stimulate the stomach. And some anti-nutritional substances. Cooked vegetables have three main goals: first, soften fiber and reduce volume; The second is to destroy the cell wall and cell membrane, and help the components in the cell transfer to the outside of the cell and be fully absorbed by the human body. At the same time, cooking can also destroy organophosphorus pesticides, remove some oxalic acid and nitrite, kill bacteria and parasite eggs, and greatly improve the safety. Of course, for many vegetables, cooked food is obviously more delicious. For example, how to eat spinach cauliflower raw? Can pumpkin be eaten raw?
What about starchy foods such as grains and beans? They not only have cell walls, but also a large number of starch granules. Starch granules are like tightly packed and packed starch layers. If they don't absorb water and swell, they won't be digested by digestive enzymes in human small intestine, and undigested hard particles will pass through the intestine, which will not only get nutrition, but also damage the digestive system.
Potatoes, sweet potatoes, yams and other potato foods can be eaten raw, but only minerals and vitamins are absorbed when eaten raw, while starch grains are basically not absorbed, and enter the large intestine like fibers, helping some microorganisms who like starch to reproduce-in this way, intestinal peristalsis is accelerated and gas production is increased. Eating occasionally is good for relaxing bowels.
Raw food doctrine: the lifestyle of aristocratic minorities
In theory, raw food can completely sustain life and provide adequate nutrition. However, the food composition of raw food is very different from that of cooked food, that is, there can be no cereal.
You can't eat whole grains and beans, and vegetables and fruits can't fully satisfy people, that is, you can eat raw fish and raw meat. Obviously, this kind of life is much more expensive than the life of "whole grains". Because an average of 5 kg of grain can be used as feed to produce 1 kg of meat, if people take fish as the staple food in China, it obviously exceeds the carrying capacity of cultivated land resources.
At the same time, fish needs to be very fresh if it can be eaten raw. This means that they are in a strict cold chain environment from slaughter to cooking, and the shelf life is only a few days. This kind of meat is obviously extremely expensive to produce.
People are also worried that fish and seafood are usually rich in environmental pollutants, and their contents of heavy metals, pesticides and other pollutants are much higher than those of cereal beans. Therefore, taking fish as the staple food, organic food must be adopted. In fact, this is exactly what raw food people have been advocating. However, it is conceivable that organically produced fish can meet the hygienic standard of raw food, with low yield and high price.
Similarly, vegetables that can meet the safety standards of raw food cannot be ordinary vegetables. Not only pesticides must be strictly controlled, but also farmyard manure that may contain parasite eggs should be used with caution. Pathogens such as Escherichia coli O- 157 should not be brought, and it is best to use clean organic vegetables. Many vegetables, especially green leafy vegetables, are not peeled as easily as fruits, and it is difficult to wash them thoroughly as tomatoes. Eating them raw is still risky.
Therefore, the thorough raw food doctrine is extremely strict with ingredients. Only a few people with aristocratic feelings can try this kind of life.
Raw vegetables: It's hard to eat more.
Although the choice of not eating food at all seems difficult to realize, it seems not difficult to eat vegetables completely raw. Beat all the fruits and vegetables into juice, or make a cold salad completely, which can be done in a Chinese kitchen.
However, the practice of eating vegetables raw is often related to insufficient vegetable intake. European and American countries mainly eat raw vegetables, but it is always difficult for them to reach the recommended amount of 1 1 serving of fruits and vegetables every day. Try it once and you'll know-
A medium-sized cabbage, if fried, can only hold one plate; If you cut filaments and eat them raw like a pizza shop, you can pack 6-8 plates. And how much salad dressing does it take to eat so many plates of vegetable salad? How much fat does it contain? The total amount of fat is more than three plates of fried cabbage.
According to the recommendation of China Nutrition Society, you should eat 300-500 grams of vegetables every day, half of which are dark green leafy vegetables. However, if you eat 200 grams of this dark green leafy vegetable raw, such as spinach, rape, cabbage, cauliflower, chrysanthemum, fennel and so on. It's too difficult. Vegetables such as beans, peas and edamame are poisonous when eaten raw. Therefore, the life of eating vegetables completely raw will greatly limit the types of vegetables. Westerners usually only eat tomatoes, cucumbers, lettuce, sweet peppers, onions and carrots raw. Many other kinds of vegetables, such as asparagus, eggplant, beet, pumpkin, cauliflower and peas, are still cooked.
It is considered a fashion for many people to drink vegetables and fruits together by beating juice or pulping. In fact, this is a method that westerners came up with to make up for the lack of vegetable intake and improve the taste of raw vegetables. Although this method will lead to enzymatic oxidation and a large loss of vitamin C and water-soluble antioxidant components, it can retain some health-care active substances in vegetables, such as components in Chinese cabbage that are beneficial to treating gastric ulcer and glucosinolates in cruciferous plants. Drinking two cups of fruit and vegetable juice every day can really increase the food intake of vegetables without increasing fat and salt, which is healthy; But if you think that you can drink fruit and vegetable juice without eating vegetables for three meals, it is all wet.
Choose raw food: do what you can according to your physique.
Many people have heard that there are many enzymes in raw vegetables and fruits, which can help digestion. In fact, for people with strong digestive ability, most of the enzymes in vegetables and fruits are killed in the stomach, because the pH value of gastric juice is as low as 2, and the enzymes in vegetables and fruits can hardly move below pH3.
For people with insufficient gastric juice and poor digestive ability, enzymes in vegetables and fruits can play a role to some extent. However, these enzymes are not necessarily beneficial. Protease helps protein digest, amylase helps starch digest, but oxidase destroys many vitamins.
The food that really helps digestion is not so much raw vegetables and fruits as fermented food. For example, unheated yogurt, fermented bean curd, fermented glutinous rice, fermented soybean and so on. Because enzymes in microorganisms often have high activity and strong heat and acid resistance, the effect is much better than that in vegetables and fruits.
On the other hand, when the body temperature is 37℃, the activity of digestive enzymes in human body is the highest. If you eat a lot of cold vegetables and fruits, the activity of enzymes in your stomach will decrease. If the body is strong and has strong heat production, the activity of enzymes can be improved by accelerating the blood circulation in the stomach; If the body is weak and afraid of cold, the heat production ability is poor, and the blood circulation is not smooth, eating too much raw and cold food is easy to cause abdominal distension, abdominal distension and other discomfort. It is for this reason that pregnant women can't eat cold food.
At the same time, raw vegetables contain more unmelted fiber, which has a certain stimulating effect on the stomach. Therefore, people with constipation are suitable to eat more raw vegetables, and people who are prone to bloating and diarrhea should avoid eating a lot of raw vegetables.
Public choice: the perfect combination of raw food and cooked food
The most important thing to remember is that cooked food never means high-fat cooking, nor does it mean that the heating temperature is too high and harmful carcinogens are produced.
Usually, food will produce toxic substances only when it is above 120℃, and the amount of these harmful substances will increase rapidly above 160℃. Among the traditional cooking methods in China, there are many cooked food methods with low cooking temperature, including steaming, scalding and stewing. Blanching or steaming vegetables quickly in boiling water can greatly improve the safety, and is especially suitable for cooking crisp and tender vegetables and green leafy vegetables. Regarding the benefits of steamed vegetables, I will write a special article in the future to provide relevant data support.
A study in the Philippines found that cooked carrots, even if only a few grams of oil, can fully absorb carotene; But if eaten raw, it takes tens of grams of oil to be completely absorbed. This is because cooking softens the cell wall and allows carotene to fully contact with oil.
Even cooking is not without its merits. Studies have shown that most of the nutrients and anticancer substances in vegetables can be preserved by quick frying without oil smoke or short-term microwave cooking. What really needs to be opposed is not cooked food, but a lot of wrong cooking methods such as oiling, high-temperature frying, overheating and even frying.
Generally speaking, whether to choose raw food depends on one's living conditions and physical condition. People with strong physique, strong digestion, high body heat, easy to get angry and frequent constipation are suitable for eating more raw vegetables, while those with weak physique, poor digestion and easy abdominal distension and diarrhea are suitable for eating less raw vegetables.
In a word, raw food and cooked food have their own advantages. For most people, it should be the best choice to eat light cooked vegetables, add some fresh and crisp lettuce and less oil in cook the meat.