Water Fasting Benefits vs. Risks: A Guide

May 24, 2020

Water fasting is a practice that has been around for centuries. In addition to being a mainstay in many cultures and religions, it is also commonly used to improve certain aspects of health, including inflammation, blood sugar levels and heart health.

With the recent surge of water fasting before and after pictures popping up across the Internet, you may be wondering just how healthy this common practice can be. In this article, we’ll take a closer look at the benefits and risks of water fasting, along with some simple tips to ensure that you’re doing it safely.

What Is Water Fasting?

A water fast, also known as a water diet, is a type of fast that involves drinking only water for a specific period of time. These fasts can last anywhere from 24–72 hours and, like other forms of fasting, food is generally restricted during fasting windows.

People try water fasting for a number of reasons. It is a common practice in many religions and is sometimes used to build faith and focus on spiritual growth. It is also used to prepare for certain medical procedures, including certain blood tests and physical exams.

Not only that, but water fasting is also associated with several health benefits. In addition to ramping up weight loss, it may also help support blood sugar control, enhance heart health, reduce inflammation and promote the turnover of cells in the body to slow signs of aging.

How to Water Fast

So can you drink water while fasting? And how exactly do you do a water fast?

Just as its name implies, a water fast involves abstaining from other foods and drinks and consuming only water. Generally, most water fasts are relatively short and last anywhere from 1–3 days. Longer fasts should not be conducted unless under direct medical supervision.

While fasting, it’s important to listen to your body closely. Although light activity may be okay for some, others may feel side effects like fatigue, weakness or dizziness while fasting.

Drinking plenty of water is also important to ensure that you’re staying well-hydrated. According to the National Academies of Sciences, Engineering and Medicine, it’s best to aim for around 90–125 ounces of fluid daily for women and men, respectively, which translates to around 11–16 cups.

It’s also crucial to break your fast the right way. Start with a light meal or snack that is easy to digest such as bone broth, cooked veggies and leafy greens. Then, slowly increase your intake and reintroduce other healthy foods back into your diet.

Potential Benefits

Fasting can be a useful tool that can help improve several aspects of health. Here are a few potential benefits of water fasting.

1. Improves Blood Sugar Control

Some research suggests that fasting could help improve blood sugar control. For instance, a 2015 study found that intermittent fasting was able to reduce blood sugar levels by an average of 12 percent in healthy, young individuals. What’s more, it may also enhance insulin sensitivity, allowing the body to use insulin more efficiently to transport sugar out of the bloodstream and into the cells.

Note that if you have diabetes or are taking any medications to lower your blood sugar, it’s important to talk to your healthcare provider before making any changes to your diet. While fasting may improve blood sugar control for some people, it can also cause side effects that can be dangerous for those with diabetes.

2. Enhances Weight Loss

Because water fasting involves severely restricting caloric intake, many people use water fasting for weight loss, hoping to shed a few stubborn pounds or kick-start their metabolism. Studies show that fasting can lead to rapid weight loss, causing an average of two pounds of weight loss per day during the first week. Fasting also forces the body to use up stored glycogen and start burning fat for fuel instead of sugar, which may promote increased weight loss as well.

However, keep in mind that most of the initial weight lost during fast is likely water weight, which is typically regained once a normal diet is resumed. Furthermore, prolonged periods of fasting can cause the body to break down muscle mass, which may reduce metabolism in the long-run.

3. Promotes Autophagy

Autophagy is a process in which damaged or dysfunctional cells are recycled, allowing the body to regenerate healthy new cells instead. Some research suggests that improving the efficiency of this process could aid in the prevention of serious conditions such as cancer, liver disease, diabetes and neurodegenerative disorders such as Alzheimer’s.

Although research in humans is lacking, several animal models have found that water fasting could help promote autophagy and slow signs of aging. According to one animal model published in Cell Metabolism, mice following a diet that mimicked the effects of fasting experienced improved cognitive performance, increased longevity, enhanced immune function and decreased risk factors for aging and chronic disease.

4. Boosts Heart Health

One of the most impressive benefits of water fasting is its ability to improve heart health. In fact, one study conducted at the TrueNorth Health Center in Rohnert Park, California found that water fasting was effective at normalizing blood pressure levels in those with borderline hypertension.

Other studies show that intermittent fasting could reduce levels of cholesterol and triglycerides, both of which are risk factors for heart disease.

5. Decreases Inflammation

Inflammation is a normal immune response that is often triggered by illness, injury or infection. Chronic inflammation, on the other hand, can contribute to a long list of conditions, ranging from cancer to heart disease and diabetes.

Interestingly, multiple studies have found that fasting could help alleviate inflammation. One study out of Saudi Arabia, for example, found that intermittent fasting altered the inflammatory status of the body by suppressing levels of proinflammatory immune cells.

Other research shows that fasting could decrease markers of oxidative stress, which can lead to inflammation and cell damage.

Related: What Is Dirty Fasting?

Dangers and Risks

Despite the potential water fasting benefits, there are several water fasting dangers to consider as well.

For starters, fasting is not recommended for children, teenagers or women who are pregnant or breastfeeding. It is also not advisable for those with a history of eating disorders as it may encourage unhealthy eating habits. Additionally, fasting may also increase the production of uric acid, a chemical compound that can trigger flare-ups of gout.

If you have diabetes or are taking medications to lower your blood sugar levels, talk to your doctor before making any changes to your diet. This is because fasting may cause changes in blood sugar levels that could be dangerous, especially if you have diabetes.

Some of the most common side effects of fasting include dizziness, weakness, muscle aches and fatigue. It may also cause dehydration, which can cause symptoms like constipation, nausea, lightheadedness and low blood pressure. During periods of fasting, it’s important to drink plenty of water to prevent dehydration.

Finally, note that prolonged fasting is not recommended unless under medical supervision. Water fasting for a week, for example, is much more likely to cause adverse side effects than fasting for shorter periods of 24–48 hours at a time. Certain forms of short-term intermittent fasting, like 16/8 intermittent fasting, are less restrictive and may be a better fit for some.

Water Fasting Tips

Whether it’s your first time fasting or you’re a seasoned pro, following a few simple guidelines is key to ensuring a smooth, safe and effective fast. Here are a few simple tips to maximize your water fasting results:

Stay Hydrated: Be sure to drink plenty of water while fasting, which can help prevent dehydration and reduce the risk of adverse side effects.
Limit Exercise: On fasting days, it’s best to keep exercise light and limit high-intensity activities. Instead, opt for low-intensity workouts like yoga, walking or biking.
Listen to Your Body: While certain side effects like hunger and fatigue are common during fasting, it’s important to listen to your body and stop if you feel unwell. You may also want to consider limiting your fasting periods or keeping a light snack on hand in case symptoms persist.
Break Your Fast Right: Although it may be tempting to break your fast with a giant feast, this can overload your digestive system and leave you feeling bloated and sluggish. Instead, break your fast with a small, easy-to-digest meal and gradually increase your intake over the course of the day.
Follow a Balanced Diet: What you eat during non-fasting days can help maximize your results. Following a healthy, well-rounded diet rich in healthy, whole foods like fruits, veggies, healthy fats and protein foods can ensure that you’re getting the nutrients you need to support overall health.

Final Thoughts

A water fast is a type of fast that involves abstaining from all foods and drinks apart from water for 24–72 hours.
Fasting may be associated with several benefits, including increased weight loss, improved blood sugar control, increased autophagy, enhanced heart health and decreased inflammation.
However, it may also cause some side effects and is not a good fit for everyone. Those who are taking medications or have underlying health conditions should talk to their doctor before making changes to their diet.
Prolonged periods of fasting are also not recommended unless under medical supervision.
When fasting, it’s important to drink plenty of water, limit exercise, listen to your body and break your fast the right way.
Additionally, be sure to follow a healthy, well-balanced diet to maximize the potential benefits of your water fast.