Nutritional diet research content

The core content of nutrition and diet research has never been to derive a universally applicable "universal healthy recipe", but to focus on the matching logic of diet and body functions in different individuals and different scenarios, covering the four core areas of basic nutritional mechanisms, population stratification adaptation, disease intervention, and dietary environmental impact. To be honest, the essence is to find the most suitable "eating plan" for everyone, rather than to produce uniforms that everyone must wear.

Many people’s impressions of nutrition research still remain in the simple conclusions of “such and such food prevents cancer” and “such and such food increases blood lipids”. In fact, even the most basic macronutrient action mechanisms are still controversial in the academic community and there is still no consensus. Take saturated fat, which everyone has been arguing about for almost two decades. The traditional dietary guideline has always been that "daily saturated fat intake should not exceed 10% of total calories." This is based on a large-sample cohort study conducted by the Harvard School of Public Health for decades, which found that excessive saturated fat intake is positively related to the risk of cardiovascular disease. ； However, in recent years, research on low-carb and ketogenic diets has suggested that unprocessed saturated fats such as grass-fed butter and cold-pressed coconut oil will not increase bad cholesterol levels, but can instead provide a stable energy supply to the body. Some teams have even conducted small-scale clinical experiments and found that replacing refined carbohydrates with high-quality saturated fats can actually reduce the risk of cardiovascular disease in subjects. Both sides are supported by solid research data, and so far there is no absolute right or wrong. In the final analysis, it still needs to be judged based on the individual's metabolic situation.

Compared with the molecular mechanisms that are still being debated in the laboratory, research on population stratified nutrition that is more practical is now the direction in which the industry invests the most resources. I had a deep understanding of this when I helped evaluate the catering for the primary school in the county town of my hometown last year. The previous school copied the catering standards for primary and secondary schools in the provincial capital city and added a box of 250ml pure milk to the children every day. As a result, in less than half a month, more than 20 children developed abdominal distension. , diarrhea. Later, after an investigation, we found out that local children had little habit of drinking milk tea and eating dairy products since childhood. Nearly 30% of the children had varying degrees of lactose intolerance. Later, we replaced half of the pure milk with lactose-free milk and room temperature yogurt, and the problem was quickly solved. You see, for the same minors, different regions and different eating habits, the appropriate nutrition plans are very different. Most of these studies now follow the scene: the nutrition plan for pregnant women should focus on the intake nodes of folic acid and DHA, the plan for fitness people should clearly calculate the timing of protein and carbohydrate supplementation, and the plan for the elderly should also consider the limitations of chewing ability and basic diseases. There is no unified standard at all.

If nutrition research on the general population is about "preventing disease," then research on clinical nutritional intervention is about "helping cure disease." There are countless controversies in this area. Take the diet of diabetic patients as an example. The older generation’s concept is “Eat less staple food, the lighter the better.” A few years ago, the low-carb school also proposed that “diabetic patients should completely abstain from refined carbohydrates and use fat for energy.” Now the latest clinical research has found that as long as the glycemic index is lower than 55, whole grains, 2-3 taels per day, can actually improve insulin sensitivity and have better blood sugar stability than patients who do not eat staple food at all. There is also the nutritional problem of cancer patients. There has been a popular saying among the people that "you must avoid eating foods, and you must starve cancer cells to death." When I was rotating in the clinical nutrition department of the oncology department, I saw many patients who were so thin that they were reduced to bones due to excessive dietary restrictions. However, they were unable to withstand the side effects of radiotherapy and chemotherapy. Now, the Domestic Clinical Nutrition Association has long made it clear that cancer patients must ensure that they eat 100 grams per day every day. Protein intake of 1.2-2g per kilogram of body weight is sufficient nutrition to support the immune system and treatment response. Of course, this does not mean that the folk dietary therapy ideas are all wrong. For example, for mild gastrointestinal discomfort, it is indeed useful to use food and medicinal ingredients such as yam and millet. However, when it comes to the stage of needing clinical intervention, you still have to follow the plan of a professional nutritionist and do not rely on folk remedies.

There is another research direction that is easily ignored by everyone, which is the combination of food environment and public nutrition. Have you noticed that now everyone basically relies on takeout to go to work, and often buy pre-made dishes when cooking at home? Even if you know how to eat healthily, you often don’t have the conditions to cook it yourself? I have participated in a nutrition labeling pilot project of a food delivery platform before. At first, I thought that the calories, macronutrients, and sodium content of each dish should be clearly marked, so that users can choose healthy ones. After the implementation, I found that the merchants found it too troublesome to calculate the nutritional data and were unwilling to cooperate. Users also had a headache looking at the dense numbers, and no one looked at it. Later, we adjusted it to a simple red, yellow and green logo: Green is Low in oil, low in salt and high in nutrition, suitable for daily consumption. Yellow means moderate and should be eaten no more than 3 times a week. Red means high in oil, sugar and salt, and can be eaten once in a while. After the implementation, the proportion of users in the pilot area choosing green meals increased by 17%. This is the significance of this type of research: It is not to force everyone to cook for themselves and become a nutritionist, but to give ordinary people more and easier healthy choices in the existing food environment.

After nearly 8 years of nutrition-related work, my biggest feeling is that nutrition research is never about giving everyone prohibitions, saying you can't eat this and not touching that, nor is it about drawing a perfect recipe for you to eat every day. All research conclusions must ultimately be meaningful when applied to specific people and specific life scenarios. Next time you see something on the Internet saying, "You can lose weight by eating such-and-such food" or "Such-and-such food is a carcinogen", be more careful. Just take a look at these conclusions taken out of context. If you really want to adjust your diet, it is better to feel more about your body's state after eating, and then slowly adjust it based on reliable research conclusions. It is worse than any universal diet.