In previous articles, we have talked about diabetes-related knowledge many times and mentioned diet control many times, but there are still many people asking these questions in private messages. Recently, a diabetic friend was very confused. I feel uneasy, and I feel confused because I look up relevant information on the Internet, because there are many inconsistent and even contradictory information on the Internet, especially when it comes to diet control, I feel a lot of pressure to choose the right food every day.

I suggested that he could use “continuous continuous blood glucose monitoring”, also known as a continuous blood glucose meter, to observe for a period of time, and then he gradually mastered the principles of dietary choices, but in some cases he still had doubts: I was eating the same weight of rice noodles and pasta. When I found that the blood sugar fluctuations were still different, I looked at the nutrients, and they were roughly the same. Why are the effects on blood sugar different? In addition, it is said that eating depends on the glycemic index, but I found that sometimes eating foods with a low glycemic index may also have large blood sugar fluctuations. Why?

What is the glycemic index? Why does it affect blood sugar?

This involves the glycemic index and glycemic load of food. The “quality” and “quantity” of carbohydrates in food and other foods eaten at the same time will affect blood sugar fluctuations after eating. After eating, the food will be digested and broken down, and the carbohydrates in it will be converted into glucose for the body to absorb, and the blood sugar level will rise accordingly. Common carbohydrate-containing foods such as rice, bread, noodles, etc. have different structures or components, and the speed at which the body breaks them down will vary, and the rise in blood sugar after eating may also vary.

The glycemic index or glycemic index (GI), which is a measure of the effect of carbohydrate-containing foods on blood sugar , is defined as the comparison of a test food with a reference food, measured numerically within 2 hours of ingesting both The relative value of the blood sugar rise. 50 grams of pure glucose is a commonly used reference food, and its glycemic index value is set as 100. When the glycemic index of a food is greater than or equal to 70, it is designated as a high-glycemic food.

The higher the glycemic index of the food, the closer the blood sugar rise after eating the food will be to the rise caused by eating pure glucose. When the glycemic index is less than or equal to 55, the food is a low-glycemic food , which means that the blood sugar rises relatively slowly or less after eating. Because the glycemic index is designed for carbohydrate-containing foods, it is not suitable to apply to non-carbohydrate foods (such as meat or protein, etc.).

Glycemic Index = (Area under the blood sugar curve for 2 hours after eating a 50g carbohydrate food/Area under the blood sugar reflection for 2 hours after eating 50g glucose) x 100

The glycemic index is affected by many factors

1. The glycemic index of carbohydrates changes due to the characteristics of the food : foods with low starch gelatinization degree and foods rich in viscous water-soluble fiber become low glycemic index foods due to the slow digestion process;

2. The pH or form of food also affects the speed of digestion. For example, food that is broken into a paste is digested faster than when it is maintained in its original state.

3. In terms of fruits, sometimes even if you eat the same kind and the same amount of fruits with different degrees of maturity , the increase in blood sugar may also be different, because more mature fruits will have a higher glycemic index.

4. In addition, starch will make the carbohydrates in it easier to digest and absorb after being heated for a long time , which will increase the glycemic index; however, cooling the starch after cooking may reduce the glycemic index . Therefore, even if the same food is made of wheat, the rise in blood sugar after eating will vary depending on the preparation process or cooking method.

Although the glycemic index has reference value, the research data have inconsistent results: weight gain, postprandial hyperglycemia and the incidence of type 2 diabetes are related to high glycemic index foods; however, some studies have pointed out that the glycemic index is not related to glycated hemoglobin. There is no apparent causal relationship.

Therefore, there has been a lot of controversy over whether the glycemic index should be used in clinical guidelines. On the other hand, low-glycemic foods are not necessarily high-nutritive foods. For example, chocolate is rich in fat and does not increase blood sugar quickly after eating. It is a low-glycemic food, but its overall nutritional value is not too high. Therefore, the glycemic index is not the only consideration when choosing foods.

Glycemic load can better predict postprandial blood sugar fluctuations, and food matching is also the focus of control

At the same time, some scholars believe that glycemic load (GL) is a better predictor of post-meal blood glucose rise than glycemic index. If the glycemic index is simplified to represent the quality of a food, then the glycemic load consists of both quality and quantity (eating size). The glycemic load is calculated by multiplying the glycemic index of a food by the carbohydrate content of the serving and dividing by 100. A glycemic load unit is defined as the intake of 1 gram of glucose (with a glycemic index of 100).

A glycemic load value greater than or equal to 20 is a high glycemic load food, and less than or equal to 10 is a low glycemic load food. If you eat a lot of low-glycemic foods, even if the quality is good but the amount is large, the glycemic load will be higher, and the blood sugar will be more likely to exceed the target after eating. Studies have shown that using a lower glycemic load diet can make people feel fuller more easily, reduce the desire to eat sweets, help weight control and reduce the incidence of diabetes.

Glycemic load = (glycemic index of food x total intake of carbohydrates in that food) / 100

for example:

Whole wheat bread: glycemic index about 50; whole wheat bread with 20 grams of carbohydrates, glycemic load = 50 x 20 / 100 = 10

However, the quality and quantity of carbohydrates are only one of the factors that affect the rise in postprandial blood sugar. Food combinations, fasting time before meals, or the amount of exercise can also change postprandial blood sugar levels. Also, everyone responds to carbohydrates differently, and some people can also make postprandial blood sugar too high after eating foods with a moderate glycemic index.

Blood sugar control is only one part of good health. When choosing a diet, you should not only pay attention to the quality and quantity of carbohydrates, but also pay attention to the intake of protein, fiber and fat.

Under the principle of a balanced diet, you should choose moderate or low glycemic index carbohydrate-containing foods that suit you; when you cannot avoid eating high glycemic index foods, you can consider making good use of food combinations to reduce the glycemic index as much as possible, such as adding appropriate amounts of fiber, Protein or better oil can slow down the digestion and absorption of carbohydrates; avoid breaking the food into a paste or cut it too finely when cooking, and use the whole fruit instead of fruit juice when eating.

In addition, psychological and physiological factors can also affect blood sugar levels. If you don’t get enough rest, get sick, or are emotionally stressed, your body may secrete stress hormones that raise blood sugar. Therefore, when finding suitable food, cooking methods and menus, it is also necessary to cooperate with appropriate exercise and rest, medication and regular monitoring, etc., in order to effectively control blood sugar levels from various aspects.

What are glycemic index foods? for example:

Foods with high glycemic index: white rice, porridge, glucose, watermelon, lychee, longan, etc.

Middle glycemic index foods: brown rice, sucrose, honey, bananas, mangoes, etc.

Low glycemic index foods: pasta, various beans, apples, etc.

Continuous continuous glucose monitoring helps understand the impact of diet on blood sugar

Compared with the traditional fingertip blood measurement (measurement of capillary blood sugar), the continuous blood glucose monitoring system collects interstitial fluid to evaluate the blood sugar level of the body, which can provide more continuous data, showing the blood sugar trend, so that people with diabetes can understand the fluctuation of blood sugar. These monitoring systems have gradually become popular in recent years. When used properly, people with diabetes can understand the impact of lifestyle habits on blood sugar and help them gradually improve blood sugar control in their daily routines. However, some people with diabetes become worried because of too much data. , but overall health is affected. Therefore, with the support of medical staff, the obtained data should be used effectively to properly understand the physical condition in order to be more handy in controlling blood sugar.