Is Dry Fasting the Magic Weight Loss Bullet You’ve Been Waiting For?

is dry fasting safe

If you’re trying to lose weight, it’s possible you’ve tried fasting or at least read about it. But have you heard of “dry fasting”? Dry fasting is different from most fasts because you restrict food and liquids. Doesn’t that sound fun? Recently, it’s become a popular eating pattern amongst people who believe eliminating water can help shed excess weight, improve blood sugars and cholesterol profiles, and boost their overall health.

The Cultural and Religious Roots of Dry Fasting

For thousands of years, devout Muslims practiced dry fasts during the month of Ramadan. The Jewish tradition of Yom Kippur is traditionally a dry fast from sundown the day before Yom Kippur, to one hour after sunset on a holy day. In some cases, all contact with water is avoided, including for bathing or recreation. 

These spiritual fasts offer ritual cleansing and atonement, self-awareness, the practice of self-discipline, and the opportunity to get closer to one’s God. 

How it Works

If you decide to embark on a dry fasting journey,  there are no set dry fasting stages or guidelines. You’ll restrict liquids and food during your fasting window, and then eat and drink as you typically would during your eating window.  Are you thinking, “How is this possible? How can I survive without water?” And you may be wondering if dry fasting is healthy and if it will help you achieve your health goals.

The Science Behind the Benefits

You Could Lose Fat

In 2016, the Journal of Human Nutrition and Dietetics published a study of men and women who participated in dry fasting during Ramadan. It found that almost all of the study participants experienced weight loss after a one month dry fast.  

Another study published in the International Journal of Endocrinology and Metabolism found the subjects experienced decreased body fat. But they didn’t lose any muscle tissue, which is fantastic news.

Your Blood Sugar and Dry Fasting

dry fasting benefits

Studies results are still mixed when it comes to dry fasting and your blood sugar. Research published in Singapore Medical Journal shows you could decrease your blood sugar, but you could see an increase in your LDL (low-density cholesterol), and a decrease in your HDL (high-density cholesterol). In other words, the study participants lost weight, but their biomarkers indicated poorer health outcomes.  However, this meta-analysis in 2014 found both blood glucose and LDL-C was decreased, and that in their female subjects, HDL-C increased. 

What About Inflammation?

There is a link between chronic and many health conditions. But dry fasting could help reduce the concentration of inflammatory marker TNF-ain obese adults and reduce the concentration of inflammatory markers CRP and IL-6. A systematic review was conducted in 2017, the highest form of quality evidence in the hierarchy of science. After reviewing all existing studies on Ramadan and immunomodulation, researchers concluded that “Ramadan fasting has been found to only mildly influence the immune system, and the alterations are transient and return to basal pre-Ramadan status”. In other words, influences on the immune system were of a very small scale, and temporary. 

However, the majority of these benefits of dry fasting are also found in studies of traditional intermittent fasting and time-restricted feeding. It is hard to differentiate whether the participants in these studies benefit from the fast, or from removing water and if both, to what extent was the benefit found from specifically dry fasting. As water is an essential nutrient that makes up 60% of our body, there can be many health implications and side effects of eliminating water. 

Is Dry Fasting Safe?

The idea behind dry fasting is you’ll get sufficient water intake by eating more high water content vegetables and fruits. But, If you choose to try a dry fast, you’ll want to be aware of the potential dangers. 

What About Nutrients 

You could get enough water through a combination of water, other beverages, and fruits and vegetables like cucumbers, broccoli, bell peppers, tomatoes, oranges, and strawberries. But, let’s break this down and see if it’s practical. 

If you eat 2000 calories per day, you would need about 2000 ml of water (based on the calculation of 1ml/kcal). 1 piece of orange contains 118 ml of water and 1 cup of broccoli – 80 ml. You would need to eat 10 oranges and 10 cups of broccoli every day to achieve your water targets. That’s a lot of peeling, and a lot of chewing. If you were to eat an excessive amount of vegetables and fruits in a restricted period, you may not have room for lean proteins, healthy fats, and complex carbohydrates, which are essential components of a healthy meal plan. 

Of course, this depends on the type of dry fasting you choose. You can drink enough water during your 8-hour eating window. But, if you try to drink that much water in a short period, it could take up prime “real estate” in your stomach, and you may not be hungry enough to eat whole, nourishing foods. 

Are There Other Health Complications?

You excrete water through your breath, sweat, urine, and stool. If you don’t adequately replenish your water loss, it can cause you to become dehydrated. And that can cause: 

  • A buildup of waste in your kidneys, since you are not excreting it out through the urine. 
  • An increase in your risk of kidney stones and urinary tract infections
  • A decrease in your cognition and mood
dry fasting science

A study in 2019 found that participants who did not drink water for 36 hours experienced fatigue, short-term memory loss, reduced attention, and reduced reaction time. However, rehydration with water relieved these symptoms. Increase your risk for a water-soluble vitamin deficiency.

Should You or Shouldn’t You?

If you participate in vigorous physical activity, or if you’re over 65 or under 18, dry fasting may not be for you. Like other eating patterns, if you’re living with a specific health condition, speak to your doctor before you make any significant changes to your eating plan. Finally, if you have or have had an eating disorder, it’s best to stay away from dry fasting. 

As with all eating patterns, it is a personal choice. Early research indicates dry fasting can improve your overall health and reduce your body fat. But, it’s essential you understand all dry fasting studies were done over a period of one month, and that’s not enough to draw long-term conclusions. Given the risks and dangers associated with dry fasting, it is up to you to determine whether or not it can fit into your lifestyle, and if so, take proper precautions to stay hydrated during the eating/drinking window, and choose high water-content foods along with other whole foods.

Author's bio


Trista Chan, RD, MHSc

Trista is a Registered Dietitian with her Master of Health Science in Nutrition Communication at Ryerson University, Toronto, and holds an Applied Human Nutrition degree and a graduate certificate in Workplace Wellness. Trista has diverse work experience in organizations both big and small. ...