Definition of diet and nutrition

The core definition of dietary nutrition is the entire process in which the human body actively ingests, digests, absorbs, and utilizes nutrients and other active ingredients in food to maintain normal growth and development, physiological functions, and activity capabilities, while reducing the risk of disease. It is never a rigid numerical game of nutritional ingredients, but a dynamic behavior deeply bound to individual living habits and physical conditions.

I have been a registered dietitian for almost 6 years, and the most common misunderstanding I encounter is that nutrition is equated with "making up numbers." Last week, a young girl who just graduated came to me and said that she had been eating strictly according to the calorie formula on the Internet for more than three months. She ate exactly 1,200 calories a day, 25g of dietary fiber, and 1.2g of protein per kilogram of body weight. As a result, her aunt postponed her meal for almost three months. The physical examination also revealed iron deficiency anemia. She was so groggy every day that she couldn't even go to class.

In fact, the quantitative standards that everyone is familiar with now, such as the daily 250-400g of grains and 300-500g of vegetables recommended by the Chinese Resident Diet Pagoda, are essentially group-wide universal guidance given in the field of public health. The core of this logic is to cover the basic needs of the vast majority of healthy people, without taking too much individual differences into consideration. When used in scenarios such as community science popularization and student nutritional meals, it has a high error tolerance and is easy to use.

But when it comes to individuals, the applicability of this set of standards will be compromised. This is also the reason why the functional medicine school has not advocated copying dietary guidelines: the metabolic capabilities and tolerances of people are too different. If you drink 300ml of whole milk, people who are lactose intolerant will have diarrhea for a day and cannot absorb the nutrients at all. ； There are also a small number of people who are chronically allergic to casein. Long-term consumption of casein may even aggravate skin inflammation and induce intestinal disorders. If you follow a unified standard and say "drink milk every day to supplement calcium", it will be a burden to these people. Precision nutrition, which has become popular in recent years, is more radical. It advocates customizing diet plans based on genetic testing and intestinal flora sequencing results. For example, people who carry high-risk genes for folic acid metabolism should supplement more active folic acid than ordinary people, instead of taking ordinary folic acid supplements. However, there is considerable controversy within the industry over this method of playing. Many scholars feel that the current testing data is insufficiently supportive, and the "gene-customized recipes" advocated by many commercial organizations are essentially IQ taxes and have limited clinical reference value.

To be honest, when I do consultations, I never give people a recipe for death. Think about it, if a local who grew up eating Chongqing butter hot pot strictly follows the dietary guidelines to eat no more than 25g of oil per day, it is impossible to adhere to it. Even if he grits his teeth and endures it for half a month, he may turn around and eat a spicy hot pot in revenge. Instead, he will consume more calories and the gain will not be worth the loss. The premise of dietary nutrition is sustainability first. If a plan makes you unhappy every day, no matter how perfect the numbers are, it will be meaningless. I met an old professor who was almost 80 years old before. He loved to drink two sips when he was young. He would drink 2 taels of white wine with two pieces of soy-fat pork at noon every day. He had been eating like this for almost 50 years. His blood lipids and blood pressure were normal during the last physical examination, and he was in better spirits than many people in their 60s. Are you saying his diet is substandard? But for his body, this model is the most suitable.

In fact, this is a bit like buying clothes. The dietary guideline standard is one-size-fits-all. Most ordinary people will not have a big problem wearing it. But if you have broad shoulders, long legs, or have your own dressing habits, you will definitely need to modify it to fit it properly. In addition to the macronutrients such as proteins, fats, and carbohydrates that we often talk about, micronutrients such as vitamins and minerals, there are also phytochemicals such as sulforaphane in broccoli, anthocyanins in blueberries, and tea polyphenols in tea. They are all components of nutrition. You don’t have to stick to a certain indicator. Eating miscellaneous food types is better than anything else.

After all, diet and nutrition is never a test paper that requires full marks, and there is no single standard answer. After eating it, your stomach will feel comfortable and you will be energetic. Your annual physical examination indicators will be within the normal range. Even if you occasionally get craving for junk food, there is no need to feel guilty. After all, the first thing we eat is to live a good life, not to make up for the numbers on the nutritional label, right?