Why is eating apples half an hour before a meal beneficial to lower blood sugar after a meal?

Apples are known for their health, but there are various theories about when to eat them. Some say "golden apples in the morning, rotten apples in the evening", and some say that "fruits cannot be eaten before and after meals, and fruits can only be eaten between meals", different statements make people feel confused.

The so-called pre-meal and post-meal can not eat fruit, mainly to take into account the special situation of some gastrointestinal disease patients. For healthy people with good digestion, whether the fruit is added as a cold dish or eaten before and after meals, there is no reliable evidence of health. Experimental studies have found that eating apples containing 15 grams of carbohydrates 30 minutes before breakfast has the benefit of lowering blood sugar after meals.

Eat the GI value of the apple before eating

The decline is most pronounced

Apple rice is eaten at the same time in second place

To be fair, the comparison of blood glucose responses in this experiment was done by isocarbohydrates.

In the first group, they ate 50 grams of white rice with usable carbohydrates.

In the second group, eat apples containing 15 grams of usable carbohydrates while eating rice. However, this rice is reduced, deducting 15 grams of available carbohydrates, and finally the total carbohydrate is still the same, all 50 grams.

In the third group, apples containing 15 grams of usable carbohydrates were eaten first, counting from the time of eating apples, and then eating rice after 30 minutes. This rice is also reduced, as much as the second group.

In the fourth group, first drink sugar water containing 15 grams of usable carbohydrates, the type and content of sugar is the same as 143 grams of apples, which is also 8.3 grams of fructose and 6.7 grams of glucose. After 30 minutes, eat rice, this rice is also reduced, as much as the second and third groups.

The results of the study show that if the GI value of a meal is used to express, then eating rice is 82, eating rice apples together is 64, and the way to eat apples first is actually reduced to 40! The effect of lowering blood sugar after a meal is really a bit fierce. The method of drinking sugar water first can also reduce the GI value to 69, but the effect of drinking sugar water and eating apples is still far worse.

Three fruits: oranges, apples and pears

Apple hypoglycemic effect is the most obvious,

Oranges are the weakest

However, many people may ask: to eat apples, you have to eat less rice? Who can do it? If I eat an apple before a meal and don't eat less rice, will there still be this hypoglycemic effect? Is it okay to eat pears? Is it okay to eat oranges?

These questions have also been taken into account by researchers. So, the second batch of experiments was continued. This time, we experimented with apples, pears and oranges, the three most common fruits of winter. Moreover, the amount of carbohydrates in the experiment was divided into two groups.

One group, called the equal carb group, like the previous study, deducted rice after eating fruit, and the total available carbohydrate intake was 50 grams.

The other group is called the high-carbon water group, which eats more fruit and rice at all. That is to say, in this group, after eating fruits containing 15 grams of carbohydrate, and then eating rice containing 50 grams of carbohydrate, the total available carbohydrate intake is 65 grams.

In the isocarbon group, it was found that apples had the best effect, no different from the previous experiments - eating apples 30 minutes before meals reduced the postprandial blood glucose response of rice two hours after meals by 40%. Pears are slightly worse, reduced by only 25%; oranges are the weakest, only 8%.

From the perspective of postprandial blood glucose fluctuations, the reduction effect of eating apples first is 50%. Eating oranges first is the weakest, with about 25%, which cannot be ignored. So, what about the high-carb group? Because I ate 15 grams more carbohydrates, the difference in blood sugar was not too large two hours after a meal. Eating apples and pears first had similar effects, only 17% and 20% lower, respectively, and oranges only 10%.

Moreover, even if you eat more fruit, the total amount of carb water increases to 65 grams, which is still significantly reduced compared with pure rice meals with only 50 grams of carbs. The results were already a pleasant surprise. It is explained that eating fruit before meals does not increase the blood sugar reaction, and putting fruits to eat before meals can even effectively reduce the fluctuation of blood sugar after meals.

Eat the fruit first

Limited to people with normal gastrointestinal digestive function

Finally, a few more things to be told.

1. The study was done in healthy people, and it cannot be confirmed whether diabetics can get the same postprandial blood sugar control effect by eating apples before meals.

2. The diet of eating fruit first is limited to people with normal gastrointestinal digestive function. Those who are particularly afraid of cold, people who are prone to diarrhea, and people with irritable bowel syndrome, eating an apple before a meal should be cautious. If there is an uncomfortable feeling, then don't eat it like that.

3. When using this method, the accuracy of time is very important. If you are not sure about the time of the meal, then "30 minutes ago" is not possible. For people who control blood sugar, it is necessary to ensure that they eat on time, and cannot time to go early and late, and the amount is too much or less. Just because you have eaten an apple, you must not allow yourself to skip meals.

4. For diabetics, food cannot be used as an alternative to drug treatment, but it is also necessary to pay attention to adjusting the dosage of drugs according to the effect of food. If the blood sugar decreases after a meal, the number of insulin and hypoglycemic drugs must be reduced, otherwise it is easy to cause dangerous hypoglycemic reactions.

Text/Fan Zhihong (Director of Chinese Nutrition Society, Chief Expert of Science Communication hired by China Association for Science and Technology)