Fasting earned its current place at the forefront of popular health based on its many documented benefits. While it may not appeal to everyone, fasting can help improve certain aspects of your health. Water fasting, in particular, isn’t a new idea. It’s been around for thousands of years as a practice undertaken by spiritual practitioners or people with specific health conditions.
So how does water fasting impact your body?
What is a Water Fast?
Much like the name implies, a water fast is a fast during which you only consume water. While they typically last 24 to 72 hours, some people extend them for longer time periods under medical supervision to help combat certain health issues. This increasingly popular type of fast can prove useful in certain circumstances. However, it’s not the most sustainable approach to weight loss and a healthy lifestyle.
4 Key Benefits
Fasting offers a host of well-documented benefits for your body. While you can choose from many different kinds of fasts, they all tend to offer similar benefits:
Greater Insulin Sensitivity
Insulin resistance is a big problem in the United States. An estimated 70 million to 80 million Americans currently struggle with this condition — often unknowingly. Insulin plays a critical role in taking sugar from the carbohydrates you consume and transforming it into energy or storing it for later use. When you’re insulin resistant, your body requires higher levels of insulin to handle the same amount of sugar. Research not only shows an association between elevated insulin levels and chronic diseases, heart disease, and certain cancers, but also water fasting’s ability to help increase your sensitivity to insulin.
Lower Blood Pressure
Long-term, water-only fasting conducted under medical supervision can result in decreased blood pressure. One study of 174 people with high blood pressure produced impressive results after participants fasted for an average of 10 to 11 days. Of the participants, 90 percent experienced a decrease in blood pressure that brought them out of the hypertension range.
It’s important to note that research on this topic mainly focuses on longer-term fasts instead of one- to three-day water fasts. That means you’re unlikely to experience measurable results in terms of your blood pressure by conducting a shorter water fast. If you’re interested in the blood pressure benefits, consult with your physician before fasting to establish a healthy plan.
Potential Promotion of Autophagy
Autophagy is one of the coolest things a human body does during a fast. It’s like a cellular recycling program your body undertakes while you remain in a fasting state. There’s evidence that autophagy can help reduce your risk of cancer by stopping the accumulation of damaged cell components — a known risk factor for a variety of cancers. Research also shows that autophagy can potentially offer protection against diseases like Alzheimer’s.
Because most of the evidence around water fast-induced autophagy comes from animal studies, it’s impossible to say conclusively that water fasting promotes autophagy in humans until researchers conduct more human studies. However, autophagy may represent an essential piece of the fasting puzzle.
While water fasts can promote quick weight loss — you may lose up to two pounds a day — you’re probably won’t lose the kind of weight you want to lose. Moreover, water fasting doesn’t offer a sustainable approach to weight loss. If you want to lose weight in a safe and sustainable way, you can find many other methods that will prove more effective in the long run.
3 Potential Risks
Water fasting also can pose several potential risks to your health, including:
A common side effect of water fasts, orthostatic hypotension is a condition in which your blood pressure drops suddenly as you change positions from sitting or lying down to standing. It can lead to dizziness, disorientation, and even fainting. If you experience orthostatic hypotension while conducting a water fast, you may want to try another form of fasting or, at the very least, abstain from driving and operating dangerous machinery during your fast.
While it may sound counterintuitive, participating in a water fast can easily lead to dehydration. Normally, humans take in about 20 percent of their daily requirement of water through the food they eat. Without that last 20 percent coming from your food, you’ll need to increase your water consumption or run the risk of dehydration — and the problems it can cause.
Exacerbation of Pre-Existing Medical Conditions
Some people absolutely should not undertake a water fast without first consulting a doctor. If you have any of the following medical conditions, a water fast could prove dangerous:
- Chronic Kidney Disease
- Eating Disorders
How to Conduct a Water Fast
If you’re interested in trying a water fast, here are some tips to help you do so safely and successfully:
Before Your Fast
- If it’s your first time, try reducing your caloric intake for several days before your fast to help prepare your body for the shock of no longer eating.
- Alternatively, you can try fasting for certain periods of the day (check out intermittent fasting to learn more about this approach).
During Your Fast
- For the duration of your water fast, focus on staying hydrated. Drinking plenty of water also can help you feel less hungry.
- Avoid exercise because it’ll make you sweat out crucial salt that you cannot immediately replace.
- If you feel dizzy or tired, avoid driving or operating dangerous machinery.
- Don’t extend your fast beyond 72 hours without medical supervision.
After Your Fast
- When you break your fast, resist the urge to binge. Shocking your system with too much food after a fasting period can cause some pretty uncomfortable reactions. If you’ve completed a longer fast, eating too much too quickly could actually prove fatal in certain circumstances.
- Start with small meals or smoothies for the first few days, increasing your intake as much as you feel you comfortably can. After three days at the most, you should be back to eating full meals without any issues.