Scientific knowledge related to nutritional diet

There is no universal recipe or diet that is suitable for everyone. The essence of a truly scientific nutritional diet is "an individualized plan that suits one's own metabolic characteristics, matches the physiological needs of the current stage, and gives priority to obtaining nutrients from natural foods. Any talk of "correct diet" that is divorced from personal circumstances is one-sided.

I came across two typical cases a while ago: one was a young man who had just been exercising for half a year. He followed the blogger for three months and ate the "standard muscle-building meal" of quinoa, chicken breast and broccoli. However, his body fat did not drop much. First, it was found that the uric acid was twice the normal value - he has a familial weak purine metabolism. Chicken breast and quinoa are medium-to-high purine foods, so eating them every day will not cause problems. The other was a girl who had been a vegetarian for five years. She always felt that she was not nutritious enough. She bought five or six imported vitamins from overseas and ate them in double the amount every day. In the end, her physical examination revealed that she had accumulated vitamin A poisoning. Her alanine aminotransferase was three times higher than the normal value, and her liver was damaged.

Don’t say that these two are exceptions. Too many people now regard nutritional diet as a standardized math problem and think that it is just right to follow a fixed formula. However, in fact, there is no absolute unified standard in the nutrition field, and the suggestions given by scholars in different research directions are inherently different. For example, the "Dietary Guidelines for Chinese Residents" promoted by the public health field is a universal framework based on the health data of more than a billion ordinary people. One pound of vegetables and half a pound of fruits, cereals and potatoes account for 1/2 of the staple food, and 120-200g of animal foods per day. These general directions are perfectly fine as a reference for healthy people. However, if you have basic problems such as diabetes, gout, and irritable bowel syndrome, it is easy to cause problems if you apply them directly. On the other hand, the personalized nutrition testing currently advocated in the field of functional medicine, testing vitamin levels and food intolerances, can indeed help special groups find a more suitable diet plan, but there is no need for ordinary people to spend thousands for testing, but they are easily cut off.

Speaking of which, I have to mention the topic of "quitting sugar" that has been particularly controversial recently. One side says that free sugar is the root of all evils such as obesity, acne, and aging. Even the sugar in fruits should be avoided. The other side says that as long as the total calories do not exceed the standard, eating sugar has no effect at all. The two sides are arguing. In fact, the truth is not that complicated: the recommendation given by the WHO is the daily intake of free sugar. No more than 10% of the total calories, preferably within 5%. The free sugars mentioned here are additional added sucrose, fructose, fructose syrup, etc., such as the sugar in milk tea, cakes, and cola. The sugar in fresh fruits is endogenous sugar wrapped in dietary fiber. It rises slowly and comes with vitamins and minerals. It is perfectly fine to eat 200-350g a day. Are you really craving for a piece of cream cake? It's absolutely fine. If you eat less half a bowl of rice for dinner that day and walk an extra 2,000 steps, the calories from the sugar will have been offset long ago. There's no need to feel guilty. Those who force you to quit sugar completely are either those who deal with diet anxiety or sell anti-sugar products. Just listen.

There is another question that everyone often asks: Should I take supplements? The views of the two sides are also very different. One group says that eating well is enough for nutrition, and supplements are all IQ taxes. The other group says that vegetables nowadays are grown in greenhouses, and their nutrient density is half that of a few decades ago, so supplements must be taken. In fact, there is no unified answer to this question. If you have three regular meals and can eat enough vegetables, meat, and eggs, then you really don’t need to take extra supplements. You might as well spend that money to buy two more pounds of fresh strawberries. But if you eat takeout all year round and don’t eat less than half a kilogram of vegetables every day, then it’s no problem to take an ordinary multivitamin supplement; pregnant women need to supplement with folic acid, vegetarians need to supplement with vitamin B12, and the elderly need to supplement with vitamin D and calcium. These are the needs of specific groups of people, and they really can’t be ignored. I once met an aunt who was in her 60s. Her bone density had reached the level of osteoporosis. She still believed that supplements were harmful and refused to take calcium and vitamin D. As a result, she slipped and fractured her femoral neck when she went out in the winter. Of course, we cannot go to the other extreme. There was a little girl who took more than a dozen supplements a day, such as whitening pills, liver protection tablets, collagen, and grape seeds. The liver enzymes she took increased in the end, and her liver was damaged before her face became whiter. It is completely unnecessary.

In the seven or eight years I have been doing nutrition consulting, I have never given clients a fixed diet at the beginning. I usually ask them to keep a food diary for three days, including whether they have gas, acid reflux, and whether they feel sleepy after a meal. They are even asked to measure their 2-hour post-meal blood sugar several times. The diet plan they finally come up with is truly suitable. For example, some people told me that everyone said that sweet potatoes are a healthy staple food, but their blood sugar is higher after eating sweet potatoes than eating white rice, so they can just replace it with yams or corn; some people have diarrhea after drinking pure milk, so there is no need to insist that they must drink milk to supplement calcium. Instead, they can replace it with Shuhua milk or eat some cheese, the calcium content is not low at all. To be honest, the most important thing about a nutritious diet is not "correctness", but that you can stick to it for a long time. If you eat something you can't swallow every day for the so-called health, and you can't stick to it for half a month and then eat a hot pot meal, it will hurt your body even more.

Actually, a nutritious diet is never something that requires you to count calories to one decimal place with a textbook, nor does it mean that you have to eat expensive foods such as avocados, quinoa, and salmon to be healthy. If you feel comfortable in your stomach, have enough energy, and have normal physical examination indicators after eating, then that is the most suitable nutritious diet for you, and it is more effective than any standard answer given by experts.