As we all know, reducing energy intake in the diet is a prerequisite for effective weight loss. For most people, 50% to 60% of the daily energy intake is provided by staple food (food, such as rice, buns, biscuits, bread, sugar, snacks, etc.). Therefore, it is not difficult to understand that obese people must first reduce the intake of staple foods. However, eating too little staple food will have an adverse health effect. So, how many staple foods should I eat when losing weight?

　　 First, let''s calculate the "minimum value" of eating staple foods when losing weight. Staple food mainly provides sugar (such as starch), which is the main (but not the only) source of human blood glucose. In the body, an important function of sugar is to assist the smooth metabolism of fat (the term is called "anti-ketone effect"). That is, if there is not enough sugar, fat cannot be smoothly metabolized into CO2 and H2O, but accumulated in the body in the form of "ketone bodies" (general term for various acidic substances). When the ketone body accumulates to a certain degree, it causes ketemia and ketonuria, which affects the body''s function, and in severe cases can cause acidosis. Therefore, it is generally advocated that at least 100 grams of sugar should be ingested per day (and some people claim that 50 grams) of sugar is safe. In addition to staple foods, sugary foods include milk (250 ml of milk contains about 10 grams of sugar), vegetables (1 kilogram of vegetables contains about 20 grams of sugar), and fruits (200 to 300 grams of fruit contains about 20 grams of sugar Type), carbohydrates, eggs and other foods have very little sugar (estimated at 5 grams per day). In this way, 45 grams of sugar (100-10-20-20-5=45) need to be provided through the staple food every day. The sugar content of most grains is about 75% (based on dry weight of raw materials), so to provide 45 grams of sugar, you need to consume 60 grams of staple food (45÷75%=60), which is 1.2 grains (dry raw materials) Recount).

　　 Then, calculate the "highest value" of eating staple food when losing weight. When you lose weight, you should reduce your energy intake. No more than 1600 kcal per day is an energy value that most people can refer to. This energy is provided in proportion by the three nutrients protein, fat and sugar. Generally, the energy supply ratio of protein is 15%~20% (here estimated at 17%), the energy supply ratio of fat is 25%~30% (here estimated at 28%), and the energy supply ratio of sugar is 50%~60 % (Here is 55%). In other words, sugar should provide 880 kcal energy (1600×55%=880). And because each gram of sugar in food can provide 4 kilocalories of energy, 220 grams of sugar should be consumed every day (880÷4=220). To remove 250 ml of milk, 1 kg of vegetables, 200 to 300 grams of fruit and other foods containing sugar (as above, estimated to be 55 grams), you also need to provide 165 grams of sugar as a staple food (220-55=165). The sugar content of most grains is about 75%. Therefore, to provide 165 grams of sugar, you need to consume 220 grams of grains (165÷75%=220), which is 4.4 grains (based on dry weight of raw materials).

In summary, the daily staple food (based on the dry weight of raw materials) consumed by people who lose weight should not be less than 1 or 2 and at most not more than 4.5. At the same time, to ensure 250 ml of milk, 1 kg of vegetables and 200 to 300 grams of fruit and meat and eggs intake.