Water fasting what is it

Katz says. Trouble is, people also tended to die, because when fuel supplies dip too low, the body starts shopping for calories from its own stores. Bhatia says water fasting can strain the kidneys and lead to nutrient deficiencies as well. That same muscle wasting that water fasting can trigger can lead to excess protein delivery to the kidneys, which makes these organs have to work harder.

Other side effects may include fainting, brain fog, fatigue, and in women, alterations in hormone levels if done for a prolonged period, she says. Fainting, brain fog, and fatigue is likely the result of low blood sugar from not eating, notes Harvard Health Publishing. For example, a small study published in in the journal Clinical and Experimental Obstetrics and Gynecology found that after one month of Ramadan fasting, the hormonal changes in 30 women were statistically insignificant.

This can set you up for yo-yo dieting , which wreaks havoc on your metabolism and can have other negative health effects. Even worse?

There are no proven benefits of water fasts, so most registered dietitians, including Kennedy, advise against doing them. Certain individuals should avoid them because they can pose serious health harms. Those people include those with kidney disease, those on multiple medications, or women who are pregnant or nursing, Taz says. She also cautions people with diabetes, heart disease, and liver disease from doing this on their own.

If you want to get to a healthy weight, look at water fasting not as a diet but a tactic that you try for a few days before returning to eating. Not confident that those two options are doing the trick? This is where water fasting might come into play. Aim to drink 9 to 13 cups of water a day, divided throughout the day, and use reminders to make you sip, Smith says. You should also look out for signs of an electrolyte imbalance, including fatigue, headache, and nighttime leg cramps.

In extreme cases, this could lead to refeeding syndrome , which occurs when there are rapid shifts in fluid and electrolytes in your body. This can cause severe, debilitating symptoms like fatigue, confusion, seizures, and heart failure — particularly if you had a longer water fast. Consuming a large, high-calorie meal after a water fast could be counterproductive for your health. If you fasted for a prolonged period, it may be best to gradually increase the size of your meals back to normal over the next 1 to 3 days.

Research on other fasting regimens has shown fasting can improve blood pressure. This includes studies that have looked at calorie liquid diets which are similar to fasting and fasting during Ramadan , a monthlong period when Muslims fast from sunrise to sunset.

According to a study , intensive fasting may help people with type 2 diabetes improve their blood sugar levels and potentially eliminate the need for insulin and other diabetes medications. However, if you have diabetes, you need to get your healthcare team on board before you start fasting, because there are risks.

Fasting may help regulate your levels of leptin, a hormone that controls your fullness. Leptin resistance is legit a thing, and it can keep you from feeling satisfied with what and how much you eat. Fasting may improve your cholesterol levels, potentially decreasing your risk of heart disease. Specifically, it may increase your high-density lipoprotein HDL cholesterol while decreasing your triglyceride levels — both very good things.

HDL-triglyceride ratio also may be an indicator of heart disease and type 2 diabetes risk. Fasting can help your body burn through stored fat, including the harmful fat that can build up on your liver and impede its function. One study found that Ramadan fasting may help improve fatty liver disease. A study found that fasting may starve tumor cells while helping to protect noncancerous cells from traditional cancer treatments like radiation and chemotherapy.

This could help keep the body stronger during treatment, resulting in fewer side effects. But more research is needed to verify the link. Certain foods can affect blood work results. This also decreases your risk of postsurgery infections, nausea, and vomiting. Drastically restricting your food intake may lead to rebound weight gain by altering your hunger hormones. A safe and sustainable rate of weight loss is 1 to 2 pounds per week. If you still really want to try fasting to shed a few pounds, intermittent fasting may be a better option.

Unfortunately, no human studies have investigated the link between short-term water fasts 24—72 hours and blood pressure.

Insulin helps the body store nutrients from the bloodstream, while leptin helps the body feel full 16 , Research shows that water fasting could make your body more sensitive to leptin and insulin.

Greater sensitivity makes these hormones more effective 18 , 19 , 20 , For example, being more insulin sensitive means your body is more efficient at reducing its blood sugar levels. Meanwhile, being more leptin sensitive could help your body process hunger signals more efficiently, and in turn, lower your risk of obesity 22 , There is some evidence that water fasting may lower the risk of chronic diseases like diabetes, cancer, and heart disease 2 , 24 , In one study, 30 healthy adults followed a water fast for 24 hours.

After the fast, they had significantly lower blood levels of cholesterol and triglycerides — two risk factors for heart disease Several animal studies have also found that water fasting may protect the heart against damage from free radicals 2 , Free radicals are unstable molecules that can damage parts of cells.

They are known to play a role in many chronic diseases Moreover, animal research has found that water fasting may suppress genes that help cancer cells grow. It may also improve the effects of chemotherapy Keep in mind, only a handful of studies have analyzed the effects of water fasting in humans.

More research in humans is needed before making recommendations. Research shows that water fasting may lower the risk of many chronic diseases and promote autophagy. However, most research is from animal or short-term studies. More studies are needed before recommending it. Because a water fast restricts calories, you will lose a lot of weight quickly. In fact, research shows that you may lose up to 2 pounds 0.

Although it sounds strange, a water fast could make you dehydrated. Symptoms of dehydration include dizziness, nausea, headaches, constipation, low blood pressure, and low productivity. To avoid dehydration, you may need to drink more than usual Orthostatic hypotension is common among people who water fast If you experience orthostatic hypotension while fasting, you may need to avoid driving or operating heavy machinery.

Because it is not a practice that is widely endorsed by the mainstream medical or nutritional community, there are no uniform guidelines for water fasting. Most of the available tips and practices come from first-person accounts of fasts shared by advocates without any medical or nutritional credentials.

There are a limited number of alternative medicine clinics that offer supervised water fasts. Many who undergo water fasting in a clinic environment begin the process with a referral from their healthcare provider. In a clinical environment, patients are monitored regularly for signs of distress such as a foul taste in the mouth, lower back pain , skin rashes, discharges from mucous membranes, headaches, irritability, nausea, or vomiting. Regular blood and urine tests are also performed. Many who perform water fasts at home do so without professional support and without the safety net provided by medical supervision.

Because it is a fairly straight-forward process, people may follow instructions found online or in magazines. You generally drink at least 2—3 liters of water per day ideally water consumption would be at the higher end of that range because you will not get the water you normally get from food.

Water fasting is harmful but can be especially detrimental to people with certain medical conditions. People who should not try a water fast include those with:. Women who are pregnant or breastfeeding and people who are under the age of 18 should also not water fast.

Additionally, if you are a smoker, managing an addiction, or regularly take a prescription or over-the-counter medication, seek the personalized advice of your healthcare provider before fasting. Additionally, it is unclear whether or not the fasting procedure itself can lead to positive outcomes.

For example, simply reducing your sugar or sodium intake for a few days may provide a benefit. And for those who drink regularly, avoiding alcohol for several days or more may eventually lead to weight loss and a reduction in blood pressure even with no other diet changes. To achieve many, if not all, of the purported health benefits of a water fast, there are often safer, healthier approaches.

For example, you might try reducing your sodium or alcohol intake as part of a healthy diet instead. The USDA Dietary Guidelines offer recommendations and tips for a balanced diet , which should include a variety of vegetables, fruits, grains, lean meats, beans, legumes, nuts, seeds, dairy, and healthy oils. The water fast excludes all of these healthy food groups with the exception of water, so it does not adhere to USDA guidelines and is therefore not considered a healthy way to lose weight.

As a short-term diet, however, you may see some weight loss during a water fast, but only for a few days. When you restrict your caloric intake for 24 hours or more, you will likely experience temporary weight loss. Keep in mind that this weight loss is probably in the form of water weight and glycogen stored carbohydrates , and not actual fat loss. It takes a few days for your body to begin burning stored fat because it uses available energy like glucose and glycogen first.

A healthy diet and regular exercise are integral to successful long-term weight loss. Use the following tool to calculate how many calories you should consume each day to reach your weight loss goals. Due to the restrictive nature of water fasting, this diet does not adhere to USDA guidelines and is not considered a healthy way to lose weight.

Rapid weight loss in the form of water weight is not sustainable for long-term weight management. Despite the risks associated with water fasting, there is some research that suggests there may be a few possible health benefits. When done in the short term, water fasting may have the potential to affect the following. Lower Blood Pressure. Drinking more water and consuming less salt are two things associated with lower blood pressure readings.

A water fast will enable you to do both of these things, which could help manage blood pressure. Medically supervised water fasts have shown to be effective in lowering blood pressure in patients with borderline hypertension. However, these patients fasted for an average of nearly two weeks—much longer than the recommended hour maximum water fast.

Promote Cell Recycling. Every day, your cells are broken down and recycled. Unfortunately, the research on the relationship between water fasting and autophagy in humans is far too limited to know for sure. Lower Your Risk of Heart Disease. There is limited evidence that water fasting can help with heart disease. One study enrolled 30 apparently healthy volunteers into a hour water fast. Help Protect Against Diabetes. Research shows that fasting of any type may help to improve insulin sensitivity.

There are several potential benefits to water fasting, but the science is inconclusive and does not position water fasts as healthful in humans. While there may be some health advantages of fasting with water, there are some clear drawbacks that should be considered.