Recently, a message exploded on the Internet. According to the authors, if the human body does not eat for 16 hours, two functions are activated: one is that the liver glycogen is depleted and the body begins to digest fatAnother function is called "autophagy", which is to eat oneself.
Screenshot of Weibo.
Seeing this, many readers and friends may wonder: Why is it that I have been hungry for less than a day, and I have really been eaten by myself?What exactly is this autophagy reaction?
Let's start with the truth:Starvation, or long-term calorie restriction, can indeed boost the body's autophagy response. However, there is no clear answer to how long it takes to starve to initiate the body's autophagy response.
What exactly is autophagy?
The word autophagy is a Greek word for "auto-" meaning "self" and phagy is derived from "phagein", meaning "to eat". Therefore, autophagy does refer to "self-devouring", and it is appropriate to say that it eats itself.
But it's a cell biology concept that began in the 60s of the 20th century, when researchers observed that cells could wrap some parts of themselves, send them to acidic lysosomes for degradation, and then recycle the degraded products. It's likeBreak up unwanted LEGO toys into small pieces so you can use them to assemble other new shapes
Japanese scientist Yoshinori Osumi has made important contributions to the field of autophagy. He set up his own laboratory in 1988 and then focused his research on protein degradation. He foundAs long as the yeast cells are starved, they will initiate an autophagy reaction, digesting the parts they don't need to maintain the necessary physiological response to keep themselves alive.
This is a bit like the story of "cutting shares and serving the king" in ancient books, in order to prevent the later Jin Wengong Chong'er from starving to death, Jie Zitui cut off a piece of meat on his thigh and made it into soup for Chong'er to supplement nutrition. knew that it was to demolish the east wall and make up the west wall, but it was also a last resort.
References.
Yoshinori Osumi then discovered a number of genes that are essential for the autophagy response, and then revealed that autophagy is a complex process that is tightly regulated by cells and is the result of natural evolution. MoreoverNot only yeast, but also in human cells, there is almost the same autophagic reaction.
Thanks to Yoshinori Osumi and other scientists who study autophagy, we now know that autophagy controls cells and uses them to degrade and degrade their own components, thereby providing energy to cells or bringing new raw materials to their metabolism.
What's more, autophagy is linked to our health – it can eliminate bacteria and viruses that invade cells, it can also allow embryos to develop normally, and it can also fight cellular aging by removing damaged cell contents. If autophagy is disrupted, it can lead to diseases such as Parkinson's disease and diabetes.
More than 50 years after the concept of autophagy was proposed, Yoshinori Osumi made us aware of its important role in physiology and medicine. It is for this reason that in 2016, the Nobel Committee awarded the scientist that year's Nobel Prize in Physiology or Medicine for his "discovery of the mechanism of the autophagy response."
Starved for 16 hours
Can the autophagy reaction be initiated?
In Yoshinori Osumi's research, by starving yeasts, it was possible to initiate their autophagic reactions. But in the human body, is it really like the hot information on the Internet, starvation for 16 hours can start the autophagy reaction?The question is complex.
According to the Cleveland Clinic, a well-known hospital, in animal studies, if they are starved for 24 to 48 hours in a row, their autophagy reaction can basically be initiated. In the human body, what is certain is -Being hungry or restricting calories for a long time can indeed promote autophagy. However, due to the lack of data, there is no clear answer to how long it takes to starve to induce autophagy
It cannot be said that there is no research in human beings at all. A 2018 review of autophagy** listed 35 studies on autophagy, of which only three were from humans. In these studies, the time required to initiate autophagy varied, ranging from 36 to 72 hours and up to 3 to 15 years. As for the 16 hours on the Internet, I have not seen a clear source and basis.
In addition, in animal models, it has been confirmed that autophagy has health benefits by removing damaged cellular parts, cleaning up faulty proteins, or destroying foreign pathogens. So now the pharmaceutical industry is also developing drugs for autophagy, wanting to use it to ** diseases.
Starved for 16 hours
Can it really be **?
Interestingly, the 16 hours mentioned in the online message are related to another hot research topic. This involves a concept called "intermittent fasting" that has been proposed in recent years, which refers to concentrating meals on a few short hours each day and starving the rest of the day. The most common method of "intermittent fasting" happens to be 8 16, which means that you eat for 8 hours (e.g. 9 a.m. to 5 p.m.) and skip meals for the remaining 16 hours.
This method has been very successful in animal experiments and has been shown to improve the physical function of animals and even prolong their life in addition to helping experimental animals**.
A 2019 study published in the journal Cell found that this "fasting" can reduce the number of monocytes in mice and humans, and that these cells produce a variety of inflammatory-promoting cytokines that can induce chronic inflammation. In an animal disease model, mice that had intermittent fasting for 4 weeks showed significant improvements.
In January, a study in Cell Metabolism found that intermittent fasting in mice helped remodel the expression of genes throughout the body, causing most tissues throughout the body to have a more synchronized circadian rhythm, which also marked an improvement in metabolism.
References.
Other studies have revealedNot only to be hungry, but also to pick the right time to be hungry。A 2021 study in fruit flies found that only those that started hungry at night and starved until noon the next day would get a clear benefit from starvation and have a significantly longer lifespan. Conversely, if you "eat supper" at night, even if you are hungry for the same amount of time and eat the same amount of food every day, the flies will not get the benefits of being hungry.
This time-related hunger is thought to be related to autophagy. This is because animals have a biological clock in their bodies, and it is only at night that the autophagy reaction is most active. If food is ingested at night, the body mistakenly thinks that it needs to be active, and it inhibits autophagy. Over time, the garbage in the cells will not be cleaned up in time, but it will be harmful to the cells.
However, it should be noted that this theory seems to make sense, but after all, it comes from animal experiments, and it is still unknown whether it can be applied to humans.
Intermittent fasting is very effective for **, reducing calorie intake is the core of what can be really effective**, and there is currently no authoritative health institution that will recommend fasting to people**
Conclusion
There is some truth in the online news that starvation can initiate autophagy. But we should pay attention to a few points:
First of all,It's not like starving for 16 hours to kick off the body's autophagy response, and there isn't much research to prove it。However, the fasting time confirmed in a small number of human studies to initiate the autophagy response often takes 2 to 3 days, which may not be suitable for ordinary people
Second, autophagy is a normal physiological function of the human body, and even if you are not hungry, you can start it by exercising or reducing your calorie intake.
Thirdly, "intermittent" hunger can indeed have a positive effect on the body, but the reasons are very complex, and autophagy is only part of it, as wellThere is currently no authoritative health agency that would recommend fasting to people**.
Finally, it is important to emphasize that if you want to be healthy, you also need to take a scientific approach. Trying not to eat or drink for a few days just to "start the autophagy reaction" may not be effective, but it will damage your body.
*丨Scientific refutation of rumors.