The human body is able to go without air for 5-10 minutes, without water - from 3 to 8 days. But without food we can stretch more than 70 days! Why is this possible?
The answer lies in a series of physiological and metabolic processes that work to hold us alive as long as possible. The fact that you are starving, does not mean that you become helpless. That's what your body is doing to preserve the activity while you are deprived of food, and give you the chance to still get food.
0-6 hours after the last pischiVskore after you eat, your body begins to break down glycogen - polysaccharides containing carbohydrates - for the production of glucose. When you eat properly, glucose is the main energy supplier. Glycogen also plays the role of "safety stock" at a time as admission glucose externally terminated.
It should be noted that not all people get the energy from the "burning" glucose. If you stick to a low-carbohydrate diet and / or doing intense weight training, your body is in ketosis, ie it has an elevated level of ketone bodies - compounds that are formed during digestion of fat instead of glucose. From a technical point of view, if you do not starve ketosis, despite the lack of glucose, you are just in a different mode of metabolism.
6-72 hours after the last pischiA now you're starving and therefore enter into a state of ketosis, in any case: your glycogen stores are depleted and the body does not remain nothing more than to produce energy from fat stores. This is the first significant metabolic phase shift since you stopped eating.
In ketosis you live as they lived, except that the brain can not use fatty acids as a fuel source. Therefore, in the first 24-48 hours of fasting brain will consume glucose residues stocks while the rest of the body is shifted in mode ketosis. The problem is that the brain needs daily 120 grams of glucose that an adequate amount of sugar contained in the three banks cola. Therefore, glucose, you will be sorely missed. The idea is that the brain will have to die. But this will not happen, because your body will do something like backup.
Firstly, ketone bodies are transformed in a way that still overcome the blood-brain barrier that prevents them from entering the brain. The brain, in turn, adapt to consume ketones, extracting of them up to 30% of the necessary energy for 3 days. Starting from the 4th day of the amount of this energy will increase to 70%. In addition, the brain learns to treat 30 g of glucose instead of the 120.
What is surprising is that humans are the only species of animal having a brain that is able to do without glucose. Apparently, it was a gift of evolution, allowing us to go through more than one period of prolonged fasting.
More than 72 hours after the last squeaks at least your brain still lacks about 10 grams of glucose per day. And there is no place to take her more than to proteins of your own body. At this stage a hunger strike a protein in the cells of the body starts to break down, releasing amino acids into the bloodstream. These amino acids in the liver is converted to glucose and brain happy again.
But it is not your body. You have entered a phase of autophagy, in a literal translation - samopozhiraniya. This does not mean that you pull yourself Gnaw limb for sustenance. This means that your muscle mass rapidly destroyed. Fortunately, the body is able to balance this process by selectively destroying the less important for the life of cells and supporting more important.
SmertPonyatno that, despite all these maneuvers, your body is not in order. Hunger nullifying the immune system, mainly due to the deficiency of vitamins and minerals. Theoretically, you can always die of immune related diseases.
But the more likely that you will still continue to live in the above mode, as long as the resources of the body - glucose, fat, muscle cells - will not completely exhausted. The final stage of starvation will be accompanied by two diseases: marasmus and kwashiorkor (severe dystrophy, against the backdrop of a lack of protein).
Insanity start due to the extreme shortage of energy due to insufficient amounts of protein and calories. Kwashiorkor edema and lead to an increase in the liver, due to which your stomach bulges to, like hungry children in the terrible pictures from disadvantaged areas. Increased stomach creates a feeling of tension, contrary to logic and you begin to feel full.
The final phase of prolonged fasting - death - will cause a heart attack or arrhythmia because of the extreme degradation of the tissue caused by autophagy, and also due to a serious electrolyte imbalance.