Apples are known to be healthy, but there are various theories about when to eat them.
Some say "golden apples in the morning and rotten apples in the evening", while others say "you can't eat fruit before and after meals, and fruit can only be eaten between meals". Different views make people feel confused.
The so-called saying that fruits cannot be eaten before and after meals is mainly due to the special circumstances of some patients with gastrointestinal diseases.
For healthy people with good digestion, there is no reliable evidence that fruit is harmful to health, whether it is eaten as a cold dish, or before and after meals.
An experimental study found that eating apples containing 15 grams of carbohydrates 30 minutes before breakfast has the benefit of lowering postprandial blood sugar.
GI value of apples before meals
The most obvious decline
Apple and rice at the same time ranked second
To be fair, the comparison of blood sugar responses in this experiment was done on the basis of carbohydrates.
The first group ate straight white rice with 50 grams of available carbohydrates.
The second group ate an apple with 15 grams of available carbohydrates, along with rice.
However, this rice is reduced in quantity, 15 grams of available carbohydrates have been deducted, and the total carbohydrates are still the same, at 50 grams.
The third group ate apples containing 15 grams of available carbohydrates, starting from the time of eating the apples, and then eating rice 30 minutes later.
This rice is also reduced in quantity, as much as the second set.
The fourth group first drank sugar water containing 15 grams of available carbohydrates. The type and content of sugar were the same as 143 grams of apples, 8.3 grams of fructose and 6.7 grams of glucose.
Eat rice after 30 minutes. This rice is also reduced in quantity, as much as the second and third groups.
The research results show that if the GI value of a meal is expressed, then eating rice is 82, eating rice and apples together is 64, and eating apples first is actually reduced to 40!
The effect of lowering blood sugar after meals 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 is still far worse than eating apples.
Oranges, apples and pears
Apple has the most obvious hypoglycemic effect.
Oranges are the weakest
However, many people may ask: should you eat less rice if you eat apples?
Who can do it?
If I eat an apple before a meal and eat a bite of rice, will it still have this hypoglycemic effect?
Is it okay to eat pears?
Is it okay to eat oranges?
这些问题，研究者也考虑到了。于是，继续做了第二批实验。这次，用苹果、梨和橙子这三种冬天最常见的水果来做实验。而且，实验中的碳水化合物数量又分成了两组。
一组叫等碳水组，和上一项研究一样，吃水果之后扣减了米饭，总的可利用碳水化合物摄入量都是50克。
另外一组叫高碳水组，额外多吃水果，米饭一点都不少吃。也就是说，这一组中，吃含15克碳水的水果之后，再吃含50克碳水的米饭，总的可利用碳水化合物摄入量是65克。
在等碳水组当中，发现还是苹果的效果最好，和前面的实验没区别——餐前30分钟吃苹果，把米饭餐后两小时的餐后血糖反应降低了40%。梨就略差点，只降低了25%；橙子效果最弱，只有8%。
从餐后血糖波动的角度来说，先吃苹果的降低效果是50%。先吃橙子最弱，也有约25%，这也不可忽视了。那么，高碳水组的情况怎么样呢？因为多吃了15克碳水化合物，所以餐后两小时血糖差异不太大。先吃苹果和梨的效果差不多，分别只降了17%和20%，橙子只降了10%。
而且，即便多吃了水果，碳水总量加到了65克，和碳水数量只有50克的纯米饭餐相比，餐后的血糖波动仍然有显著降低。这个结果已经很令人惊喜了。说明餐前吃水果并不会额外升高血糖反应，而且把水果放到餐前来吃，甚至还能有效降低餐后血糖的波动。
先吃水果的饮食方式
仅限于胃肠消化功能正常的人
最后还要叮嘱几件事。
1.该研究是在健康人当中做的，还不能确认糖尿病人饭前吃苹果是否能得到同样的餐后控血糖效果。
2.先吃水果的饮食方式，仅限于胃肠消化功能正常的人。那些特别怕凉的人，容易发生腹泻的人，有肠易激综合征的人，餐前吃个苹果还是要慎重的。如果有不舒服的感觉，那就不要这么吃啦。
3.用这个方法的时候，时间的精准很重要。如果不确定用餐时间，那么“30分钟之前”也就无从谈起了。对控血糖的人来说，必须保证按时用餐，而不能时间忽早忽晚，量忽多忽少。决不能因为吃了苹果，就放任自己到点不吃饭。
4. For diabetic patients, food cannot be used as a substitute for drug treatment, but it is also necessary to adjust the dosage of drugs according to the effect of food.
When blood sugar levels drop after a meal, the amount of insulin and hypoglycemic drugs must be reduced, otherwise dangerous hypoglycemia reactions may occur.
Text / Fan Zhihong (Director of the Chinese Nutrition Society, Chief Expert of Science Communication hired by the China Association for Science and Technology)