Everything You Need to Know About Water Fasting
Written and Medically Reviewed by Ioannis Nikitidis MD, MSc, BSc on January 24, 2020.
Restricting food intake or fasting has been used for thousands of years whether it's for religious or spiritual reasons, to lose weight or just combat a certain health problem. Water fasting is a type of fast that restricts everything except water. Read on to find out everything you need to know about water fasting including the benefits, potential dangers and essential water fasting tips.
What is Water Fasting?
As the name suggests, a water fast is a type of fast where you don’t consume any food or drink except for water. Herbal teas or black coffees don’t count, you can only drink water. This may sound tough but the health benefits can be profound. Fasting is nature’s way of allowing your body to cleanse, detox and heal itself.
There is no set time for a water fast but generally, they can last anywhere from 24 hours to three days. This duration is considered safe for most people however it’s down to the individual and their needs as to how long the fast can be. Water fasting for over a week isn’t uncommon.
There are several reasons why you might try a water fast such as:
- To detox
- Religious reasons
- To lose weight
- For its health benefits
One of the main reasons people try a water fast is for its health benefits. Several studies have shown a connection between water fasting and health benefits including a lower risk of certain cancers, heart disease, and diabetes.
Popular diets have actually been modeled after the water fast such as the lemon detox cleanse. This involves drinking a mixture of water, lemon juice, cayenne pepper and maple syrup for up to seven days.
The Benefits of Water Fasting
Everyone can benefit from a water fast. Whether you’re looking for the occasional cleanse or suffer from certain conditions like obesity or digestive disorders. Fasting is a powerful tool with numerous health benefits and long-term protective effects. With an overweight, aging and stressed population, water fasting is a great way to keep your waistline under control and take a preemptive strike against disease. Here are a few water fasting benefits.
Autophagy is the process in which your old cells are broken down and recycled. Evidence suggests that autophagy may help to protect against certain diseases like Alzheimer's, cancer and heart disease. Research in animal studies has shown time and time again that water fasting helps to promote autophagy. Further animal studies have found that autophagy may even help to extend lifespan.
Lower the Risk of Several Chronic Conditions
Water fasting may help to lower the risk of certain chronic conditions such as cancer or heart disease. In one study of 30 healthy adults, following a 24-hour water fast, participants reported significantly lower levels of cholesterol and triglycerides. These are two big risk factors for heart disease.
Several studies have also found that water fasting may protect the heart against free radical damage. Free radicals are unstable molecules that can damage cells, causing illness and aging. It’s thought that water fasting is able to lower the risk of disease due to its ability to protect against free radical damage and promote autophagy. Some evidence suggests that water fasting may even suppress genes that encourage cancer cells to grow.
Reduce Blood Pressure
Research suggests that medically-supervised long-term water fasts may help to lower blood pressure in people with high blood pressure. One study found that after a 14-day water fast, 82% of participants who had borderline high blood pressure, saw their blood pressure fall to healthy levels.
Another study found that after an 11-day water fast, 90% of participants with high blood pressure experienced reduced levels in blood pressure. There appears to be a clear connection between blood pressure and water fasting, benefiting individuals who struggle with high blood pressure levels.
Boost the Immune System
Water fasting gives the body the ability to detox, cleanse and reboot. Research from the University of Southern California shows that water fasting for just three days can actually regenerate the immune system. This makes water fasting extremely promising in terms of immune problems, and for all of us as we age, as the immunity naturally lowers as get older. By temporarily restricting your food intake, your mind and body have the chance to heal and truly tap into your greatest potential.
Support Weight Loss
The amount of weight you lose on a water fast depends on your body and the duration of the fast. You will mainly lose water weight in the beginning, fat burning doesn’t tend to kick in until around day two. When the body doesn’t have access to carbohydrates, it’s preferred source of energy, it starts to use up fat as energy, therefore, resulting in weight loss.
Improve Leptin and Insulin Sensitivity
Insulin and leptin are crucial hormones in the body that affect your metabolism. Leptin helps you to feel full while insulin helps the body to store nutrients from the bloodstream. Some studies have found that water fasting could make you more sensitive to insulin and leptin. Increased sensitivity means that the hormones will act more effectively.
If you’re more insulin sensitive then your body is more efficient at lowering blood sugar. Whereas, if you’re more leptin sensitive then your body is better at processing feelings of fullness and hunger signals which in turn can lead to a lower risk of obesity.
The Potential Dangers and Risks of Water Fasting
So, you’re probably thinking is water fasting safe?
The answer is yes but as with anything, there are potential water fasting dangers and risks that you should be aware of when deciding whether to fast or not.
You May Feel Dehydrated
This may sound odd as all you’re drinking is water, how could you be dehydrated? Well, if you’re drinking the same amount of water you usually drink then you have the potential to feel dehydrated. This is because an estimated 20% to 30% of your daily water intake comes from the foods you eat. Symptoms of dehydration include headache, dizziness, nausea, and constipation.
Keep an eye out for these symptoms and listen to your body. Most people tend to drink two to three liters of water per day on a water fast.
It May Worsen Some Health Conditions
There are certain health conditions that may be made worse by a water fast, therefore, some individuals should avoid water fasting. If you have any of the following conditions then you should consult a medical advisor before considering a water fast.
Health conditions that may interact negatively with a water fast include:
- Individuals with eating disorders or are severely underweight
- Chronic kidney disease
- Pregnant or breastfeeding
- Taking specific medication for a health condition
- Heart problems
- Extreme athletes who are in season
May Cause Orthostatic Hypotension
Orthostatic Hypotension is a type of low blood pressure that can make you feel lightheaded and dizzy. It basically means that when you stand up you can experience a sudden drop in blood pressure and feelings of dizziness. Evidence suggests that it can be common in people who are water fasting. This is important to take into consideration if you’re operating heavy machinery as it does present a risk of fainting.
Water Fasting Tips
Water fasting can be both physically and mentally draining so preparing yourself before the fast is essential. If you’ve never fasted before, start off slowly with a 24-hour water fast to introduce you into it. Before you begin the fast, eat foods that are high in energy, preparing your body for the fast.
If your schedule allows it, try choosing a day when you have time to rest and adjust. If you’re feeling unwell or very tired, postpone the water fast until you feel healthy and ready to go. Avoid doing any really demanding exercise during the fast as well.
Here are some other water fasting tips to help prepare your body and mind:
- Build a low-stress schedule
- Move your body
- Avoid negative people
- Try and stay out of the kitchen if possible
- Let yourself rest
The idea of a water fast can feel a little daunting and if that’s the case you can build up to it slowly. You can do this by reducing your meal sizes to begin with as well as intermittent fasting. One thing to remember is that after you’ve finished your water fast, try to resist indulging on the biggest meal you’ve ever made. The post-fast phase is important, especially with longer fasts. Start off by breaking your fast with smaller meals or protein shakes with high-quality ingredients or even a bone or vegetable broth.
Eating a large meal straight away may lead to uncomfortable symptoms. The post-fast phase usually lasts up to a day however for longer fasts you may need up to three days for your body to adjust and be able to eat regular-sized meals. Always listen to your body and prepare mentally and physically before a fast.
What to Expect
You’re probably wondering what to expect and what water fasting results you might experience. You may notice feelings of tiredness when first starting out your water fast. After all, you are eliminating food from your daily intake which your body isn’t used to. On the first day, expect to experience hunger, mood changes, and increased urination.
Depending on your body and length of water fast, you may start to feel better and experience more mental clarity as the time goes on. Many people who take part in water fasting often report significant weight loss and just feeling better overall. Water fasting can have a transformative effect on an individual, helping to clear the body of toxins and boost overall wellbeing.
How much weight can you lose if you fast for 3 days?
Water fasting results can change from person to person. There are a number of factors that impact how much weight you lose including your metabolic rate, sodium levels and how much glycogen you have stored in your body, therefore, a water fast may impact you differently. If you’re on a high-carb diet then you would lose more weight than say a person who is on a ketogenic diet. If you’re not eating for three days, then you will likely lose weight.
How long is it safe to fast on water?
Some individuals fast for two days and some two weeks. Before taking part in a long-term water fast of over three days, it’s always best to consult a medical professional. Some individuals experience benefits from a 5-day fast while others fast for just 48 hours and feel a boost. Water fasting is considered safe and has been used for thousands of years.
What are the health benefits of water fasting?
Water fasting has been linked to numerous health benefits including weight loss, increased leptin and insulin sensitivity, improved blood pressure and its ability to lower the risk of several chronic conditions such as cancer and heart disease.
Can you die from water fasting?
Technically if you fasted indefinitely and didn’t eat you would enter a state of starvation. However, the body has evolved over thousands of years to go periods of time without food by storing it as fat. Always do your research and consult your doctor if you’re considering long-term water fast. Water fasting offers several health benefits and for most healthy adults going without food for several days should cause little to no harm.