What Is Water Fasting And Should You Try It?

Fasting has been practiced in many major religions for centuries. Water fasting is a type of fasting where you only drink water for a period of time—usually 24-72 hours—and ingest no other food or beverages. People water fast for many health reasons such as weight loss, to “detox,” for spiritual reasons, and more.

While there aren’t many studies done on humans on fasting and its benefits, the few there are do seem to show several benefits.

Read on to learn more about the potential benefits of water fasting, and if it’s right for you.

Benefits of Water Fasting

Few studies on fasting have been conducted on people, but the studies that have been done show some promise. Much of the benefit of water fasting hinges on the fact that fasting can help induce a state of nutritional ketosis, which is when your body stops burning glucose (carbohydrates and other sugars) as energy and instead burns fat for energy.

Some of the health benefits of water fasting may include:

May Treat Hypertension

Almost half of all American adults have hypertension (high blood pressure), which is when the pressure from your blood against your artery walls is consistently too high. Hypertension can increase your risk for heart disease and stroke.

An older study of 174 participants with borderline hypertension, guided the participants through a medically-supervised fast for 10-11 days. The results showed that blood pressure was reduced to normal ranges in 90% of the participants. However, while the study was well-designed, it was only done on a small group of people. Additionally, the participants did not fast alone. Since the fast was long, they were at an inpatient facility and underwent medical check-ups twice a day for safety.

May Reverse Type 2 Diabetes

Nearly half of all Americans live with diabetes, prediabetes, or metabolic syndrome, which increases the risk of developing type 2 diabetes. Diabetes is a condition where your cells are less sensitive to insulin, which helps your body turn food into energy and regulates your blood sugar levels.

Studies show that fasting may make your cells more sensitive to insulin. A group of researchers conducted a small study with 36 people with diabetes and had them fast intermittently over the course of three months. The study results showed that 90% of participants reduced the diabetes medications they took-including insulin—and that more than half of the participants saw their diabetes go into remission.

May Improve Heart Health

Heart disease is the leading cause of death in the U.S., and nearly 1 million Americans experience a heart attack each year. Researchers think that occasional fasting may protect against heart disease by reducing oxidative stress in your body, and inducing nutritional ketosis.

Studies even show that fasting after a heart attack can impact several risk factors for heart disease positively, like high blood pressure, high cholesterol, diabetes, and obesity.

May Reduce Your Risk of Several Diseases

Autophagy is a process where cells break down any old or damaged parts and then recycle them within your body. If this process is disrupted, your risk for several diseases increases, including cancer and neurodegenerative diseases, like Alzheimer’s disease. Fasting is a well-recognized way to encourage autophagy, meaning occasional short fasts could reduce your risk for several diseases.

Risks and Side Effects

Though there may be some benefits to water fasting, it's certainly not for everyone. People with certain medical conditions like type 1 diabetes or chronic kidney disease should not fast. If you take medications, you discuss with your healthcare provider before starting a fast.

Fasting can also increase your risk for orthostatic hypotension—dizziness when you stand up—due to a sudden drop in blood pressure. This may cause some people to experience falls and injuries.

Another risk of water fasting is hyponatremia, when the level of sodium in your blood is too low, due to drinking too much water. When you sweat, you lose sodium and other important minerals. Replenishing with water only can cause an electrolyte imbalance. Therefore, it’s important not to exercise or sweat profusely while doing a water fast.

Water fasting may be harmful to certain people, including anyone with the following conditions or experiences:

• Eating disorders: People with a history of eating disorders, or who tend to have disordered eating behaviors are encouraged not to fast. Water fasting may lead to more disordered eating or may begin the binge-restrict cycle.
• Certain ages: If you’re younger than 18 or over the age of 65, it’s not recommended that you undergo a water fast. Children under age 18 are still growing and need nutrition from regular meals. Fasting has not been studied in older adults.
• Pregnancy or breastfeeding: Your nutritional and caloric needs increase when you are pregnant or breastfeeding, and anything you do can affect your unborn baby. Fasting is not recommended for anyone who is pregnant or breastfeeding.
• Diabetes: People with type 1 diabetes should not water fast. With type 2 diabetes, you should always speak with your doctor before fasting. If you do a water fast with diabetes, there is a risk of hypoglycemia (low blood sugar). If you take insulin or other diabetes medications, going without food may require altering your medications, which you should never do without your doctor’s approval. Fasting may be helpful for type 2 diabetes, but always talk to your doctor first.
• Chronic kidney disease: People with chronic kidney disease are normally advised not to fast, as it may worsen the function of their kidneys. But some studies find that people with up to stage 3 of chronic disease may fast under close supervision from a healthcare provider.
• GERD: If you have gastroesophageal reflux disorder (GERD) or frequent heartburn, fasting may worsen your condition. Your stomach will continue to make stomach acid, even with no food to digest, which may worsen your symptoms. 
  

How To Water Fast 

Water fasting is not widely endorsed by modern medicine, so there is no official medical protocol for it. Some people choose to fast for 24-72 hours, or 1-3 days. You may want to try a one-day fast first, to make sure you have no adverse effects.

If you choose to water fast, begin your fast at a time when you are able to rest more. Choosing to fast during a busy time, or when you’re exercising or working hard may make the fast more difficult.

Some people like to prepare for a fast by eating smaller meals the day before, or for fasting for part of a day. That can help your stomach get used to less food. Other than that, some people do a water fast by sipping water throughout the day, and avoiding food and other beverages. That means no coffee, tea, diet soda, or anything else.

There are some alternative health centers or naturopathic doctors that guide their patients through extended fasts. For those types of fasts, you should speak with your healthcare provider to see if it is recommended for you. Many of those programs require a referral from a medical professional.

Is Water Fasting For You? 

Water fasting might work out for you if you don’t have any of the conditions listed above, and if you don’t take any medications. If you do decide to try a water fast, there are a few things you should keep in mind. 

Without regular food and electrolytes, you may feel tired and experience brain fog. Going too long without food may deprive you of essential nutrients your body needs. It’s also important to remember that in just a few days of fasting, you may lose weight, but it might not be fat loss. Instead, any weight loss you lose could be water weight or even the loss of lean muscle mass.

It may be surprising since you are drinking water throughout the fast, but dehydration is still a risk. Hydration is about more than drinking water, it’s also about replenishing your body of electrolytes, important minerals that your body needs to work properly. Electrolytes, like potassium, sodium, and magnesium come from food. If you fast for too long, you may feel ill without these necessary minerals.

When To See a Healthcare Provider

If you want to try a water fast, it’s always a good idea to run it by your healthcare provider first. If your job is physically demanding, ask your doctor if water fasting is right for you.

If you take certain medications or are living with an illness, don’t start a water fast until you have been cleared by your doctor. If you choose to water fast and you experience adverse effects, it’s a good idea to see your healthcare provider and discuss the problems you experienced.

A Quick Review

Water fasting may have several health benefits, but it does come with some drawbacks. It can be tricky for people with type 2 diabetes, because it does seem to improve the condition, but it can be difficult to manage. If you feel that water fasting is right for you, it’s wise to clear it with your doctor first and plan carefully.