Which organ of the body is affected most on keeping fast for a long time?

Author: Dan Powlowski  |  Last update: Sunday, January 4, 2026

Keeping fast for a long time has the greatest effect on the kidneys of the body.

Which organ is affected by fasting?

The most immediate organ affected by a fast is the pancreas. During times of low plasma glucose, the pancreas will release more glucagon from the alpha cells found in the islets of Langerhans. Glucagon will mainly affect the liver as it stores most of the glycogen in the body.

Which part of the body is most affected by fasting for a long time?

Long-term fasting has the greatest effect on the kidneys.

Can fasting cause organ damage?

Good preparation and planning can avoid problems during fasting. Dehydration can have a negative impact on the kidneys, building up a waste and acids in the body, and potentially leading to kidney stones, urinary tract, kidney damage and disease if left untreated.

Which is the fastest functioning organ of our body?

The eye: the fastest muscle in the human body | Novartis.

The Truth About Fasting: What Really Happens to Your Body?

What is the fastest regenerating organ?

The liver has a unique capacity among organs to regenerate itself after damage. A liver can regrow to a normal size even after up to 90% of it has been removed.

Which organ is the most powerful organ?

Brain. The brain is the body's control center. It forms the core of the central nervous system by creating, sending, and processing nerve impulses, thoughts, emotions, physical sensations, and more. The brain consists of three main subparts: the cerebrum, the cerebellum, and the brainstem.

Does fasting damage the liver?

Various researchers have reported that fasting may lead to improvements in liver function, potentially indicating a reduction in liver fat accumulation or inflammation. Additionally, total cholesterol levels, which are known to be associated with NAFLD, may also improve during this fasting period.

What is the long term damage of fasting?

Research Highlights: A study of over 20,000 adults found that those who followed an 8-hour time-restricted eating schedule, a type of intermittent fasting, had a 91% higher risk of death from cardiovascular disease. People with heart disease or cancer also had an increased risk of cardiovascular death.

Is fasting good for your pancreas?

Fasting triggers a particular mechanism that helps beta cells in the pancreas manage glucose, according to discovery scientists at Mayo Clinic. The paper, published in Science Advances, reports that this molecular mechanism explains why intermittent fasting supports normalized glucose concentrations.

What is the best food to eat after fasting?

After fasting, your body needs gentle food options to ease back into digestion. Focus on hydrating, easy-to-digest foods — think light veggie soups, simple smoothies, or bland foods like rice or toast. Avoid foods that are high in fiber, fat, sugar, or spice.

What does prolonged fasting lead to?

Results reveal that prolonged fasting for 5-20 days produces potent increases in circulating ketones, and mild to moderate weight loss of 2-10%. Approximately two-thirds of the weight lost is lean mass, and one-third is fat mass.

Does fasting put stress on the heart?

According to the researchers' presentation (PDF, 373KB, 1 page), people who limited their eating window to less than eight hours a day had a 91 per cent (almost double) increased risk of dying from heart and circulatory diseases, compared to those who had a more typical eating window of 12 to 16 hours.

How many days do you need to fast to cleanse your body?

Many medical experts agree that a one-day fast can feel great. But extending beyond three days can begin to cause harm, especially if you have other medical conditions, such as diabetes or heart disease. “A fast longer than a day or two can deplete vitamins, minerals and electrolytes,” Dr. Hopkins says.

What happens to intestines during fasting?

When the digestive tract is put temporarily at rest during periodic fasting, it remodels its structure leading to a reversible atrophy as shown for rat intestinal villi(10). In addition, changes in gut motility, total intestinal mass(11) and microbiota composition have been described in the gut of fasting animals(12).

How fasting affects your lifespan?

During fasting, cells undergo an adaptive stress response that may account for its many beneficial effects. Alternate-day fasting improves markers of oxidative stress, a measure of longevity. Intermittent fasting has shown to protect against many age-related diseases including diabetes and cardiovascular disease.

What is the negative impact of fasting?

As much as IF is filled with benefits, there are mild side effects that can happen during fasting, which do not generally require medical or surgical treatment. Possible side effects can include dizziness, nausea, insomnia, headache, weakness, etc. [6].

What does fasting do spiritually?

Overall, fasting is an important spiritual discipline that can help you draw closer to God, humble yourself before Him, resist temptation, seek His guidance, and show solidarity with others. By fasting and praying, you can grow in our relationship with God and become more obedient to His will.

Can fasting damage your organs?

Yes, it is possible to lose calories, fat and weight from this popular diet. However, it is also possible to quickly gain the weight back, develop low energy stores which can result in a depressed mood, have problems sleeping and even develop organ damage if the fasting is extreme.

Does fasting affect your kidneys?

Effects in humans

In a pilot study in 13 patients with chronic kidney disease, cycles of the fasting-mimicking diet were kidney-protective, including reducing proteinuria and improving endothelial function compared with patients who did not receive dietary intervention.

Does fasting shrink your liver?

Fasting resulted in a significantly reduced liver mass but only had a minimal effect on bodyweight. The effects on the liver by 30 days of fasting were not reversed by subsequent ad libitum refeeding for 30 days.

What is the most protective organ?

Among its many functions the skin is an incredible organ always protecting the body from external agents.

What 12 organs can you live without?

You'll be surprised as to how much you could lose and still live. You can still have a fairly normal life without one of your lungs, a kidney, your spleen, appendix, gall bladder, adenoids, tonsils, plus some of your lymph nodes, the fibula bones from each leg and six of your ribs.

What is the most critical organ?

The brain is arguably the most important organ in the human body. It controls and coordinates actions and reactions, allows us to think and feel, and enables us to have memories and feelings-all the things that make us human.

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