To control blood sugar, is it better to take a walk after a meal, or to exercise on an empty stomach?

A female colleague asked me: How can I eat a lot without gaining weight?

I said: You are not overweight, you don’t need to eat less at each meal to starve yourself, don’t eat snacks indiscriminately, and control greasy food.

If you want to prevent obesity for a long time, the measures are actually very simple: don't sit down and watch TV and play with your mobile phone after a meal as before, but quickly stand up, take a walk, or do housework. At least half an hour.

She followed suit and told me a few months later: After-meal activities really work.

She asked: Why does it have this effect?

I said: By doing this, the body will know that it has to work after a meal. Instead of rushing to store the energy it eats into fat, it needs to distribute part of the energy to the muscles. In this way, it is not easy to gain fat.

Another friend asked me: What is the easiest way to control blood sugar?

I said: eat on time and according to the amount, the food is complete with meat, and then stand up for a walk immediately after the meal, and do some housework for at least half an hour. Do not sit still immediately, let alone lie down to sleep after a meal.

A few months later, she told me: on the days that I can meet these requirements, my blood sugar is really well controlled.

But why start the activity right after the meal?

I said: Postprandial activity can reduce the postprandial blood sugar peak through the consumption of blood sugar by muscles, which is also conducive to reducing blood lipids. Of course, these effects are also beneficial for obesity prevention.

But they were confused and asked: Some experts suggested that it is better to exercise on an empty stomach before meals, and to sit or lie down for half an hour after meals to facilitate digestion. But you told us to go for a walk right after dinner, who is right?

I explained: In blood sugar studies, mealtimes are counted from the first bite. The so-called "30 minutes after a meal" is 30 minutes from the first bite of the meal. The so-called 1 hour after a meal is 60 minutes from the first bite of the meal.

Anyone who knows about postprandial blood sugar knows that postprandial blood sugar peaks occur between 30 and 60 minutes after a meal. Maybe 30 minutes, maybe 45 minutes, maybe 60 minutes. This peak period is the time when a large amount of insulin is most needed, which promotes the synthesis of triglycerides (increasing fat) and the production of glycosylated hemoglobin.

Therefore, the key to controlling postprandial blood sugar is to flatten this postprandial blood sugar peak. This peak is smaller, the risk of pre-meal hypoglycemia in the later period will also be reduced, the fluctuation of postprandial blood sugar will be reduced, and the risk of various diabetes complications will also be reduced.

Most people eat between 15 and 30 minutes for a meal. If you finish eating in 30 minutes, then the blood sugar peak has almost arrived. If you sit and rest for another 30 minutes, the blood sugar peak is almost over. After that, there is no way to reduce this peak by exercising again.

Therefore, we need to exercise in time and start easy activities within 30 minutes of the first bite.

One of the hazards of eating that kind of marathon dinner is that you have to sit for a few hours, and your body has no chance to do some physical activity to digest the high blood sugar, so it is very unfavorable for controlling blood sugar and blood lipids, and it is also very unfavorable for preventing obesity.

Then, the question comes again: Will it be harmful to the stomach and intestines if I exercise immediately after a meal? Will it cause appendicitis?

I said: Relaxing activities after a meal, not for running and jumping, but for washing dishes, wiping the table and walking, etc., will not cause gastrointestinal dysfunction, and there is no risk of causing diseases such as appendicitis. Unless you're a highly frail person, or you have a serious problem like a sagging stomach, it's better to lie down and sit down after eating.

For most people, taking a relaxing exercise after a meal will not only not affect digestion, but will feel very comfortable in the stomach and intestines.

Seeing this, some friends with a strong scientific spirit may ask: These two ladies are just "instances". Timely exercise after meals is beneficial to blood sugar control. Is there any research evidence?

I said: In fact, in recent years, a number of relevant studies have proved that walking immediately after a meal is more conducive to blood sugar control than activities at other times. Let's take a look at a few articles.

• A 2016 cross-over study asked subjects to go for a 30-minute walk immediately after a meal, or at other times, and compared the effects of the two practices. The results showed that walking after meals was significantly more effective in reducing postprandial blood glucose response than walking at other times. Among them, the effect of walking after dinner is the most obvious. Compared with not walking after a meal, it can reduce the area of ​​​​the postprandial blood glucose curve by 22% [1].

This result is not surprising, because the human body's ability to process blood sugar at dinner is lower than that at breakfast, and after dinner, people are most likely to watch mobile phones, watch TV, watch TV shows, surf the Internet, and sit on the sofa without moving.

• A 2017 cross-over study divided 50 diabetic patients into two groups. One group walked for 30 minutes after getting up in the morning, but sat still after three meals; the other group did not walk before meals, and after three meals a day, Immediately after walking for 10 minutes. After 30 days, the two groups switched practices.

As a result, walking around after a meal for just 15 days significantly reduced the patient's insulin dosage. Compared with the practice of getting up early and walking, the method of standing up and walking immediately after three meals has achieved greater blood sugar control effect [2].

• Another study published in the same year divided subjects with type 2 diabetes into two groups of 32 for a cross-over controlled trial. In group A, moderate-intensity brisk walking and stretching for 45 minutes (4500-4800 steps) before breakfast, and sitting still after meals for two months; group B did not walk before meals, and immediately after 15-minute breakfast, moderate-intensity brisk walking for 15 minutes ( 1400~1500 steps), also for two months. Then, the movement patterns of the two groups were reversed.

As a result, 15 minutes of exercise after a meal reduced the postprandial glycemic response more than 45 minutes of exercise before breakfast. It is particularly convincing that those who switched from pre-meal to post-prandial activities had better postprandial blood glucose status; conversely, those who switched from post-prandial activities to pre-prandial activities had worse blood glucose status [3].

• A research review published in 2018 summarized 11 relevant studies and found that postprandial exercise can reduce the postprandial blood sugar area, ranging from 2.4% to 26.6%, and the hyperglycemia state of the day was also significantly improved, with a reduction ranging from 2.4% to 26.6%. 11.9% to 65%. Both walking and resistance exercise are effective, but moderate-intensity aerobic exercise for more than 45 minutes has the best effect [4].

Therefore, the research evidence is sufficient, and the results are quite consistent, all proving that exercise after meals is more conducive to blood sugar control!

Some friends also mumble, don't many people say that exercising before meals is more conducive to weight loss...

Weight loss is weight loss, and blood sugar control is blood sugar control. The two are not completely consistent concepts. Diabetic patients and healthy people may not be able to use the same advice.

For people with diabetes, exercising before meals carries a risk of hypoglycemia, which is more dangerous than hyperglycemia. Even if blood sugar is not considered, exercise before meals has a greater risk of muscle loss, especially if food intake is insufficient and nutrients are not supplemented after exercise. Muscle loss is a very negative impact on blood sugar control.

So, I would never recommend that diabetics put all exercise before meals. Getting up early and exercising is okay, but post-prandial exercise is essential. If you want to exercise before breakfast, it is recommended to eat a little something, such as a bowl of milk oatmeal. Exercising after energy supply is not only less dangerous, but also has more physical strength during exercise and better exercise effect.