What is an empty stomach?
Generally speaking, fasting means not eating for 8- 12 hours.
Eat at 5 pm and exercise at 9 pm, not on an empty stomach.
Exercise before meals is not fasting exercise.
In this paper, "fasting" refers to the state of not eating after getting up in the morning.
When you exercise on an empty stomach, the lipolysis activity will accelerate.
Fat decomposition is the first step of fat burning. Lipolysis needs the catalysis of enzymes, which are sensitive to some hormones, such as adrenaline, norepinephrine, glucagon, cortisol and so on.
The levels of these hormones are already high in the morning, and fasting exercise and sympathetic nerve excitement further improve the levels of these hormones. Therefore, during fasting exercise, more adipose tissue can be decomposed into fatty acids, waiting to be oxidized and utilized.
Exercise on an empty stomach in the morning, blood sugar is low, and the proportion of fatty acid re-esterification may decrease.
Re-esterification of fatty acids, in short, is to turn decomposed fatty acids into fat again.
When blood sugar is low, the process of re-esterification of fatty acids will slow down. In addition, fasting hypoglycemia may be beneficial for some fatty acids to cross mitochondrial cell membrane and enter mitochondria to be burned. When hunger, high-fat diet or sugar storage in the body decrease, the activity of a special enzyme increases, which can promote this process.
On an empty stomach, liver glycogen storage is relatively low, and blood sugar is also relatively low. Even muscle glycogen levels may not be high. Although blood sugar will rise briefly at the beginning of exercise, it is still relatively low on the whole, not to mention the long exercise time.
Exercise under the condition of insufficient sugar storage in human body, especially exercise with moderate intensity or above for a long time, will generally increase the consumption of muscle protein, which is very unfavorable for maintaining muscles.
Of course, if you can have a full meal after exercise and take in enough calories and protein, these consumed muscles can generally be replenished.
However, when we lose weight, we often don't get enough calories and nutrients, so these muscles may really be consumed, but they can't be replenished.
Hard training is to increase your muscles, burn more fat, and make muscle lines become obvious!
It is true that fasting can burn more fat, but overall, your body composition has not changed, because at the same time, your muscle mass has also decreased! That is, the same proportion decreases and the proportion of components remains unchanged.
The ultimate goal of reducing fat is to change body composition and reduce fat and body fat rate while maintaining lean body weight, and the key to changing body composition is a strategic diet and planned training!
Studies show that high-intensity exercise can still get some bonus for burning calories after exercise, which means you will burn more fat when you are at rest.
However, in order to avoid muscle loss during high-intensity exercise and continue to burn fat after exercise, you need to eat first, and fasting exercise naturally does not have this benefit.
Fasting exercise, especially high-intensity and long-term exercise, will reduce blood sugar concentration.
Blood sugar is the direct energy substance of the brain, and its concentration is too low, which may also be harmful to health. Many times, after a certain period of exercise, blood sugar is easily as low as 3, which is actually very dangerous for some people.
People with hypoglycemia, arrhythmia, hypertension and other problems should be extra careful. If the blood sugar is too low, the brain will feel tired because of lack of motivation, people will feel dizzy and weak, and some people will look pale and break out in a cold sweat. If you continue, you will be delirious and even unconscious.
Appropriate sugar supplementation will replenish energy to the brain, produce pleasant and refreshing nerve conduction substances, and make the exercise process more enjoyable and relaxed.
When you exercise on an empty stomach, you will produce a lot of nitrogen-containing waste and ketone bodies in your body. In order to excrete these wastes, your body will further produce urine and increase the amount of urine excreted, thus causing dehydration.
At this time, the body is in a crisis of insufficient energy and water. Dehydration and muscle loss will make it more and more difficult to lose weight.
Fasting exercise has a high level of plasma free fatty acids, and people with cardiovascular problems should also be careful.
Excessive stress hormone levels during fasting exercise may also bring a series of health effects, including the impact on the central nervous system, the impact on cardiac function, and the suppression of immune function.
It is not recommended for people with heart and liver dysfunction and people over 50 to exercise on an empty stomach.
Fasting exercise increases the burden on the heart and liver and is prone to arrhythmia.
At the same time, because the main energy source at this time is fat, the free fatty acids in the blood will increase significantly. Fatty acids are not only the energy source of myocardial activity, but also cause myocardial poisoning, arrhythmia and even sudden death.
People over 50 years old are at greater risk because of their weak ability to decompose free fatty acids.
People with hypoglycemia, hypertension and hyperlipidemia are not advised to exercise on an empty stomach.
Similarly, due to the high concentration of free fatty acids in plasma, platelets may stick together to form thrombus or lead to arrhythmia, so people with hyperlipidemia or hypertension must avoid fasting exercise!
There is no risk of hypoglycemia if the fasting exercise time is controlled within 60 minutes. If people with hypoglycemia symptoms at ordinary times, fasting exercise is not recommended.
It is not impossible to lose weight by exercising on an empty stomach, but I suggest you not to exercise on an empty stomach. If you must do it, please do the "optimized version"
The "optimized version" of fasting exercise is aimed at healthy people, and it is not recommended for people with exercise risks to exercise on an empty stomach!
You can do some low-intensity exercise on an empty stomach, and keep the exercise intensity below moderate or moderate intensity.
If we do high-intensity aerobic training in the morning, our bodies will not have enough glycogen reserves at this time, which will lead to our body's sugar overdraft, and we will feel very tired for a long time after training. If we don't get a good rest and food supply, it will affect our body's repair ability, thus reducing the efficiency of burning fat.
Therefore, it is suitable to do some moderate and low intensity aerobic exercise in the morning.
Moderate intensity exercise is best controlled within 30 minutes, and low intensity exercise is generally not recommended to exceed 60 minutes.
Pay close attention to hypoglycemia reaction, if you have dizziness, nausea, palpitation and other reactions, stop exercising quickly and supplement sports drinks.
Specifically, in the next paragraph,
And once again, the "optimized version" of fasting exercise is aimed at healthy people, and it is not recommended for people who are at risk of exercise to exercise on an empty stomach!
GI value, that is, blood glucose index, is an index reflecting the degree of blood glucose increase caused by food. Low GI food, after entering the gastrointestinal tract, has slow digestion and absorption, slow glucose release, low peak value after entering the blood, slow decline rate and low blood sugar level. Therefore, foods with low GI value are more suitable for eating before exercise! Recommend several foods with low GI value to everyone ~
Coarse grains: brown rice, whole wheat bread, oats, etc.
Fruits: apples, persimmons, strawberries, oranges and so on.
Beans: soybeans, edamame, etc.
Foods with low GI value can not only ensure enough energy supply during exercise, but also won't gain meat ~ awesome! Great!
Drink a cup of warm water before running to dilute the blood concentration, so as to avoid the risk of ketone poisoning caused by fat burning because the blood is too thick.
Water! Water! Water!
We often sweat like rain when we exercise ~
At this time, the body will lose a lot of water, so it is necessary to replenish water in time! Every 15~20 minutes, about 200ml of sports drinks or pure water can be supplemented, and other heavy drinks should be supplemented with small sips.
It is not recommended to eat solid food or drink protein powder during exercise, which may cause gastrointestinal discomfort. Some high-fat energy bars and chocolate bars should also be avoided.
Any exercise will consume muscles, attention, anything! Protein plays an important role in muscle repair and synthesis.
There will be a window period of muscle recovery 20~60 minutes after exercise, during which protein supplementation can minimize muscle loss.
Therefore, it is necessary to provide sufficient nutrition for the "hungry" muscles at the first time after exercise, help the torn muscle cells to accelerate their growth, and fully grasp the "golden two hours" of muscle gain!
Add it immediately after the suggestion, the sooner the better.
Different from before exercise, you should eat a proper amount of carbohydrates with high GI value after exercise.
Such as udon noodles, potatoes, corn, bananas, watermelons, etc. Stimulate insulin secretion and accelerate the synthesis of glycogen from glucose. But remember to stick to the principle of low fat and high protein.
However, if you want to lose weight, it is not recommended to supplement carbohydrates and protein after exercise.
After half an hour's rest, you can have breakfast as usual. Breakfast needs low fat and high protein. At the same time, you can eat some high-carbon and high-moisture foods, replenish glycogen in time, and further promote fat burning.
Disclaimer: All articles published on WeChat official account are only shared as popular science knowledge and cannot replace professional medical advice. If you are sick, please see a doctor in time.