Why fasting and milk, the nutritional value is not high, from a biological point of view

Drinking milk on an empty stomach is not of high nutritional value: because water accounts for a large proportion of milk, drinking more milk on an empty stomach dilutes the gastric juice, which is not conducive to the digestion and absorption of food. In addition, the intestinal peristalsis is very fast on an empty stomach, and the milk passes through the gastrointestinal tract quickly, and the retention time is very short, and its nutrients often have no time to be absorbed, so they rush into the large intestine and go through the motions.

Therefore, drinking milk on an empty stomach is not in line with nutritional hygiene. The ideal breakfast should be a protein-rich, high-calorie meal in the amount of not less than the amount eaten throughout the day. Therefore, it is best to drink milk before taking a nap or going to bed at night, which can eliminate disadvantages and benefits and better play its role.

If you are used to drinking milk for breakfast, you must also eat a little other food before drinking milk so that the milk stays in the stomach and intestines for a longer time. If you want to drink a bottle of milk for breakfast, you can eat 50 grams of rice or pasta first, add an egg and a little pickles, dried tofu, and then drink milk, so that the milk is mixed with other foods in the stomach and stays in the stomach for a longer time, which is conducive to the digestion and absorption of its nutrients. Since the food provides enough calories, digestion and absorption are slower and more sufficient, so that the blood sugar level is consistently high, and the morning will be full of energy.

Milk can be heated, but not boiled. Because after boiling, some vitamins will be destroyed, and the calcium in milk will form calcium phosphate precipitation, which affects the absorption of nutrients by the body. Boiling milk also has a certain knowledge, most people will put white sugar into milk and then add fire to boil, which will make the milk in the lysamino acid and sugar react under the action of high temperature, to produce freightyl lysine, this substance will not be digested and absorbed by the human body, but harmful to human health, so boiled milk should wait until the milk is not hot after boiling before adding sugar.

If it is a biological quiz question, just say, drinking milk on an empty stomach, milk is mainly used for oxidative decomposition to release energy, but not nutrition, so it is best to eat some starchy substances while drinking milk for breakfast, so that more milk can play a nutritional role. This is basically a full score.

Protein is difficult to digest, and it is sent to the small intestine before it is digested and absorbed.

It seems that because people still need sugar as the most direct energy**. When people refer to milk as a food, they mainly emphasize the protein supplement (milk is rich in protein). On an empty stomach, the digestive system first needs to meet the needs of calories and the like to ensure the most basic life activities, so it has to convert the amino acids obtained by protein decomposition into sugars that can be used for energy after such and such reactions (sorry, I forgot after graduating for too many years).

In this way, drinking milk is equivalent to using protein as sugar instead of protein, and it also increases the burden on the body to convert protein into sugars and excrete by-products. That's why it is said that drinking milk on an empty stomach is not of high nutritional value. Rice and wheat are rich in starch (starch is a type of polysaccharide, which is decomposed into glucose and the like, which can provide the most direct energy), so it is generally recommended to eat rice and wheat and drink milk.

Answer B: The energy supply sequence of the three major nutrients should be sugars, fats, and proteins. The main component of milk is protein, which has high nutritional value, but if you drink cow fuel milk on an empty stomach in the morning, because there is no other energy intake, the protein in milk can only be used to provide energy through deamination, that is, it is completely oxidized and decomposed through deamination and releases energy. It is equivalent to a reduction in its nutritional value.

Answer C does not eat steamed buns, only drinks milk, and the sugar-free metabolic intermediate product Zen Zheng is produced, and the transamination effect cannot occur in the burning hall, that is, it cannot produce He Duan Songxin amino acids.

(2) According to the purpose of the experiment, the experiment was divided into 2 groups, one was the experimental group and the other was the control group, and the independent variable was whether to feed sugared feed, so the feeding method was: group A was fed with 15N-labeled milk, and group B was fed with the same amount of 15N-labeled milk with sugary feed

4) From the purpose of the experiment, it can be seen that this question is a first-class experiment, so the expected experimental results and conclusions should be;

Material testing: Now there are many good and bad infant milk powders on the market, and some of them have little or no protein content, and the biuret reagent can be used to detect whether the milk powder contains protein

So the answer should be:

2) Group A was fed 15N-labeled milk, and Group B was fed the same amount of 15N-labeled milk with sugar-sweetened feed

Material testing: biuret reagent.