(1) The food itself is clean, non-toxic, pollution-free, contains no harmful substances and is harmless to eat.

(2) Food intake should keep the balance of various nutrients; Include that intake and consumption of various nutrients and the balance among various nutrient.

(3) There is a reasonable dietary system, three meals are regularly quantified, the proportion is appropriate, and the distribution of three meals should be reasonable. Generally, the energy of breakfast, lunch and dinner accounts for 30%, 40% and 30% of the total energy of a day respectively.

(4) Food should be processed and cooked reasonably to minimize the loss of various nutrients in food and improve its digestion and absorption rate. And has good color, fragrance, taste and shape, thus diversifying food, promoting appetite and satisfying satiety.

(5) Food intake should be supplied with enough energy and various nutrients to ensure the energy needed for body activities and labor; Ensure the growth and development of the body, tissue repair, maintain and regulate various physiological activities in the body; Improve the immunity and resistance of the body, and adapt to the needs of the body in various environments and conditions.

As long as the above five points are achieved, it is reasonable nutrition, which is what nutritionists say.

Nowadays, with the enhancement of health awareness, many so-called "health preservation concepts" have sprung up, some of which are summaries of experience, while others completely subvert our traditional eating habits, such as "total food".

"Whole food family" refers to people who insist on eating whole foods. They "eat grapes without spitting grape skins" and even eat grape seeds. Eating bananas is the same. Nowadays, more and more urbanites have joined the ranks.

"Whole food" believes in the view of "whole food and full nutrition", and thinks that "leftover materials" such as grape skins, grape seeds and banana skins are rich in vitamins, minerals, cellulose and plant biochemical substances. If ingested for a long time, it can resist oxidation, eliminate free radicals and delay aging.

Is that really the case? In this regard, Tang Lianhua, a nutrition expert in Panyu Hospital of the Armed Police Force, believes that the "fruit nutrition theory" advocated by the "whole food family" is difficult to cross the two barriers of "nutrition absorption" and "food safety".

Resveratrol in grape skin and grape seed does have antioxidant effect, but the grape seed shell is very thick, which is not conducive to digestion and absorption. Even if the grape seeds are crushed, they still can't meet the standard of digestion and absorption, and will eventually be discharged with excrement. Moreover, eating grape seeds will make the tongue numb, because it contains a lot of tannins, which will solidify the protein on the surface of the tongue, mouth and esophagus and produce a strong astringent taste. Therefore, it is not necessary to eat grapes with seeds in order to obtain nutrition.

In addition, banana peel contains crude fiber, which helps to excrete, but people with bad stomach will have serious problems when they eat it. Tang Lianhua said that the nutrition of food is not all in the skin and seeds, and there is no need to deliberately pursue "food integrity". The so-called "healthy and beneficial ideas" such as "eating grapes without spitting out the skin" and "eating bananas with skin" are actually unscientific and not worth emulating.