Water Fasting Has Become Super Trendy, But Is It Powerfully Healing — Or Really Dangerous?

Fasting seems to be the latest health trend, with intermittent fasting, alternate-day fasting, and water fasts becoming more familiar terms in the wellness landscape.

The success of water fasts may lie in their ability to induce autophagy, a mechanism by which the body reprograms itself, clearing out old cells or damaged cells and replacing them with new ones—a reboot, so to speak. There is also research that suggests that fasting can improve digestive health, allowing good bacteria to flourish, resulting in an overall improvement in metabolism, weight, and many other cardiometabolic conditions.

Studies show that water fasting will help you to lose weight1 (around 14 pounds in five days of water fasting), lower blood pressure2 (drops an average of 20 points after five days of water fasting), and reduce oxidative stress (a good thing, because too much oxidative stress ages you more quickly). Oxidative stress is a condition where too much oxygen can wreak havoc in your cells. It’s complicated, and that last sentence is wildly simplified, but the bottom line is that oxidative stress is an indication that you are out of balance on a cellular level. This condition can cause excessive fatigue, brain fog, muscle and joint pain, wrinkles and gray hair, poor eyesight, headaches and sensitivity to noise, and a decreased immune system.

The bad news is that water fasting for multiple days is highly challenging, and it can be dangerous. I don’t recommend a water fast for more than 48 hours unless it is medically supervised. Research also demonstrates the negative effects3 of a water fast on your kidneys and a decrease in CoQ10, an enzyme naturally produced in your cells and tissues. CoQ10 acts like an antioxidant, providing energy to our cells, preventing muscle weakness and even cardiac dysfunction.

Prolonged water fasts can also result in fainting, brain fog, and fatigue. Water fasts are not recommended for anyone with kidney disease or who are pregnant or nursing or on multiple medications.

There are spas where you can go to do water fasting under the supervision of doctors—in these places you often receive daily massages, chiropractic care, and spa baths—but you are still just drinking water for days on end (five to 40 days is the amount offered). I’ve never tried it, and I admit that it’s intriguing, but as a functional practitioner, I still think it is extreme and unnecessary. There are so many different tools to heal the body, each of which always has to be used appropriately. A one- to two-day water fast comes with minimal risk, but trying to go for more than two days with just water will likely make you irritable and increase your risk of side effects.

If you still want to try water fasting on your own (and you don't have any of the conditions mentioned above), I suggest no more than 24 to 48 hours followed by a day of green drinks and a protein smoothie. Make sure that during the 48 hours of water fasting you don’t overexert yourself since it can cause dizziness, nausea, and headaches. You can do a shorter fast and still get many benefits from doing a smart detox day with a gut-resetting tonic, a powerful green drink, and a protein smoothie. Intermittent fasting has been shown to provide all the benefits of a water fast, with none of the hunger and physical torture you have to go through.

As you navigate the world of fasting and its implications for your health, understand that fasting is essentially a form of detoxification, an opportunity to reset and reboot the body. A short water fast, intermittent fasting, a detox—there are so many options to choose from, but safety and the long-term results should always be the first goals.