Water Fasting: Benefits And Risks

Are you struggling with losing weight? Do you have frequent migraines, acne, or fatty liver disease?

These are all common reasons why people try water fasting. But is it safe?

Read below to find out who may benefit from a water fast, who should avoid one, and whether they really work.

What Is Water Fasting? How Does It Work?

Water fasting is just like it sounds – fasting from all foods and beverages except water. No tea, coffee, or calorie-free foods are allowed.

Some people insist that you stop taking supplements during a water fast. Others say that you must also give up any external-use products like lotions, deodorants, and toothpastes.

It is most likely not necessary to take give up basics like deodorant, but the choice is up to you.

Fasting is nothing new – most religions and spiritual beliefs incorporate fasting in some way. Muslims observe Ramadan, Catholics fast from certain foods during Lent, and people of Jewish faith observe Yom Kippur.

Some people do water fasts for these religious reasons, while others do it to lose weight, detoxify, or improve certain conditions.

Water fasting is usually done for 24 to 72 hours, but some people have fasted for 30 days or more. Fasts longer than 24 hours should only done under the supervision of a medical professional, as serious complications can occur.

What Happens To Your Body

Your body undergoes what is called a Fed-Fast cycle. The cycle starts when you eat your first bite of food and continues all the way through the starvation process.

Your body goes through this cycle in order to keep you alive as long as possible without food. You will experience different symptoms as you pass through each stage of the cycle.

During the first 18 hours of your fast your body will be in what is called the “post-absorptive state”.

You’ll rely on glycogen, or stored glucose, to give you energy and maintain blood sugar levels. You won’t lose any body fat during this time because of this stored glycogen.

No major side effects will happen during this time. You might feel some hunger, depending on how frequently you normally eat.

During the next 30 hours of your fast your body will enter the “fasting state”.

You will run out of glycogen and begin to rely on protein from your muscle as your main source of fuel. Your body will also begin to break down small amounts of body fat to provide energy in addition to the protein from muscle.

This is when your body will begin to form ketones, a word you may have heard associated with the trendy ketogenic diet. Ketones are the result of body fat breakdown and are harmless in normal amounts.

You’ll likely want to allow yourself plenty of rest during this time and lay off the exercise. Many people experience intense hunger, light headedness, dizziness, irritability, extreme fatigue, and flu-like symptoms during the fasting state.

2 days into your fast and beyond, you will enter the “starvation state”.

Your body will shift from relying mostly on protein from your muscles for energy to breaking down more body fat. This is the stage where you’ll begin to lose the most weight.

Production of ketones will also go up during this state. Ketones can be harmful in these larger amounts, and prolonged fasts can cause a condition called ketoacidosis.

Ketoacidosis is when the blood becomes too acidic and can be fatal if left unaddressed. Sickly-sweet breath is a common sign of ketone build up.

Many people report energy spikes during the starvation state. Symptoms common during the fasted state, such as hunger and irritability, tend to go during this stage.

What Are The Dangers?

Water fasting can be perfectly safe when done for a short period of time, or when supervised by a medical professional. Many people choose to have blood work done before, during, and after their fast to make sure organs like the liver and kidneys are not being damaged.

Children under the age of 18 should not do a water fast. Children’s bodies rely heavily on the nutrition from food to grow and develop. Fasting should also be avoided by the elderly.

People with certain medical conditions like heart disease, type 1 diabetes, kidney disease, and uncontrolled migraines should not do a water fast.

Anyone with a history of eating disorders is strongly advised to avoid fasting of any kind. Fasts can trigger disordered eating and lead to further complications.

Women who are pregnant or breastfeeding should not take part in a water fast as they need even more nutrients than usual to take care of their baby.

Will A Water Fast Help You Lose Weight?

As you might imagine, skipping food for several days will inevitably make you lose weight. Many people lose as much as 2 pounds per day on a water fast.

In shorter fasts, most of the weight lost will be water weight. This is because when glycogen, or stored glucose, is used, water is released. This also means that when you begin eating again, the water weight will come back as your body builds your glycogen stores back up.

Believe it or not, this is actually a good thing! Glycogen is what keeps your body working at night while you sleep and in between meals. Just be prepared to gain some of the weight you lose back once you start eating again.

In longer fasts, body fat will also be lost as you begin to rely on fat stores for energy. Although this will allow you to lose weight quickly, water fasting is not an effective form of long-term weight loss.

Unless you adopt healthier eating habits once you break your fast, you’ll gain back the weight you lost.

Intermittent fasting is a better method if your main goal is weight loss. It’s also a great idea to speak with a dietitian who can help you learn how to make healthier, more intuitive food choices when you aren’t fasting.

Will A Water Fast Get Rid of Migraines?

As mentioned earlier, water fasts are not recommended for people with uncontrolled migraines.

Migraines have seemingly countless causes and can be hard to treat. This leads some people to try fasting to help relieve pain, but fasting will often make migraines worse.

Migraines can be triggered by fasting if your migraines are brought on by stress, low blood glucose, caffeine dependence, or dehydration.

That being said, some people report that their migraines went away after completing a water fast.

Will Water Fasting Help Acid Reflux?

Water fasting is not a good treatment for acid reflux. In fact, it can make it worse!

Even when you aren’t eating, your body will continue to produce stomach acid. This is because stomach acid can be stimulated when you’re hungry, when you’re around food, or even if you’re just thinking about eating.

Can Water Fasting Help with Acne?

Many acne creams on the market aim to increase a process called autophagy. This is a process that is also known to happen during a water fast.

But what is autophagy?

Autophagy is a natural process where your body destroys old, dysfunctional, or unnecessary cells. It then recycles these cells and uses them to make new, healthy ones.

In theory, this process could improve the appearance of acne.

It should be noted that water fasts will not address the underlying problem that is causing your acne, whether it be a hormone imbalance, food allergy, or certain lifestyle factors like poor sleep or diet.

Can Water Fasting Help with Candida Overgrowth?

Candida is a naturally occurring yeast that lives in your intestines. In normal amounts it helps with digestion and absorption of your food.

When an overgrowth of candida occurs, either in your small intestines or elsewhere, symptoms like digestive problems, chronic fatigue, and fungal infections can occur.

Some people have tried water fasts in an attempt to “starve” the candida.  Unfortunately, it looks like there is no way to truly starve candida as long as you’re living and breathing.

Candida can use both glucose and ketones as an energy source. Glucose comes from food or glycogen and is your body’s primary fuel source. During a water fast that glucose is used up, but as a trade-off, ketones are formed.

Whether you’re eating normally or fasting, your body will provide the candida with some form of food.

It is best to work with a medical professional who is well-versed in candida treatment to resolve any overgrowth you may be experiencing.

Can Water Fasting Get Rid Of Lipomas?

Lipomas are harmless fatty lumps that form underneath the skin. They can occur whether you are underweight, overweight, or at a healthy weight.

While there is some convincing research that water fasting can help get rid of cancerous tumors, lipomas are not cancerous. This means the research will not apply directly to lipoma treatment.

There is not a lot of anecdotal evidence of people using water fasts to get rid of their lipomas, but some people feel it’s worth a try as an alternative to surgical removal.

Can A Water Fast Help With Stomach Ulcers?

Water fasting is very unlikely to help with stomach problems like ulcers. This is because your body continues to produce stomach acid even if you aren’t eating for long periods of time.

Stomach ulcers can be caused by a combination of risk factors like stress, diet, the use of NSAIDS, and bacteria called H. pylori. A water fast will help with some of these factors, but if you already have a stomach ulcer, the stomach acid produced on an empty stomach will cause extreme pain and make your ulcer worse.

Effect On Parasites

There is some evidence suggesting that water fasts may decrease the amount of parasites present in infected people.

Naturopath Dominique Julien recommends fasting, along with the use of a specific supplement, for the removal of parasites. Many people have had great success with this protocol.

Even if you see evidence of parasites dying off (such as dead parasites in your stool), it is important to get re-tested after your fast is over. This is because the parasite eggs are more likely to survive a fast and can stay in your intestines, only to hatch later and create a new infection.

How Does Water Fasting Effect the Liver?

Water fasting may be useful for fighting fatty liver disease.

During a fast, the production of a certain protein called GADD45-β is increased. This protein, when present in high amounts, is associated with decreased fat stored in the liver as well as lower blood sugar levels.

Fat gained in the liver is notoriously hard to get rid of, so fasting may be one effective method to help with this.

While fasting might help with fatty liver disease, longer term fasts can actually cause liver damage. Talk to your doctor if you are thinking of trying a water fast and have liver problems.

Effects On The Thyroid Gland

There is not much information available on how a water fast effects the thyroid gland.

The starvation state, which starts 2 days after your last bite of food, can cause hypothyroidism by causing levels of the hormones T3 and T4 to drop. The effects aren’t significant, though, and may not even be noticeable during a short term fast.

Some people believe that the autophagy caused by a water fast can be beneficial to people with thyroid problems, especially ones caused by an autoimmune disease like Hashimoto’s Thyroiditis. Right now, it is unclear as to whether this is the case.

Takeaway Notes

  • Water fasting is a fast, typically between 24 and 72 hours, during which no food or drinks other than water is consumed.
  • Water fasting can be dangerous for certain people, such as children, the elderly, pregnant or breast-feeding women, and people with certain medical conditions.
  • Water fasting will not help with acid reflux, stomach ulcers, migraines, or candida, and in some cases it can make these conditions worse.
  • There is good evidence showing that water fasts can help with fatty liver disease, parasites, and short-term weight loss.
  • Talk to a medical professional if you are planning on doing a water fast longer than 24 hours.
Kelli Yates
Kelli Yates
Kelli Yates is a health and nutrition writer, dietetics student, and co-host and creator of The Nutrition Nerds Podcast. In her spare time she teaches the free class Well-Fed Survival: Eating Healthy After A Disaster, which helps people build nutritious emergency food supplies and prepare for natural disasters.
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