At a Glance:
- Water fasting involves drinking only water for 24-72 hours.
- Research is limited, but water fasting may lower your risk of disease and decrease your blood pressure.
- Risks of water fasting include dehydration and orthostatic hypotension.
Water fasting involves drinking only water for 24-72 hours. It may help with weight loss and detox, but it lacks much research.
How Does Water Fasting Work?
Water fasting is a type of fast in which you only consume water. People typically do water fasting for 24-72 hours.
You might choose to do a water fast for several reasons:
- “Detox” the body
- In preparation for a procedure or surgery
- Possible benefits, such as decreasing blood pressure or improving heart health
- Religious or spiritual reasons
- Weight loss
What To Know Before You Start Water Fasting
Modern medicine does not widely endorse water fasting, so there’s no official medical protocol. Some people fast for 24-72 hours (1-3 days). You might try a one-day fast first to check for any side effects.
Start your fast when you can rest. Fasting during a busy time or while exercising and working hard can be hard.
Some people prepare for a fast by eating smaller meals the day before or by partially fasting. This helps your stomach adjust to less food.
What Are the Health Benefits You Might Experience?
Few human studies on fasting have been conducted. However, the existing ones show promise.
Many benefits of water fasting are linked to inducing nutritional ketosis. In ketosis, your body stops burning glucose (from carbohydrates) and burns fat for energy instead.
May Lower Your Risk of Several Diseases
Autophagy is a process in which cells break down any old or damaged parts and then recycle them.
Fasting has been shown to encourage autophagy in animal studies. Occasional short fasts could lower your risk of several diseases.
Helps Manage Type 2 Diabetes
Nearly half of all people in the United States have diabetes, prediabetes, or metabolic syndrome, which increases the risk of type 2 diabetes.
Research has shown that fasting may make the cells more sensitive to insulin, lowering your risk of diabetes.
May Treat Hypertension
Almost half of all adults in the United Staes have hypertension (high blood pressure). Hypertension causes the pressure from the blood against the artery walls to be too high.
Water fasting may decrease blood pressure.
Might Improve Your Heart Health
Heart disease is the leading cause of death in the United States. Occasional fasting may protect against heart disease.
Fasting after a heart attack can positively affect several heart disease risk factors.
Are There Any Risks To Watch Out For?
You may develop complications from water fasting.
Increases Your Risk of Dehydration
Surprisingly, dehydration is a risk with water fasting. This is because you may not be getting the electrolytes your body needs.
Electrolytes, like potassium, sodium, and magnesium, come from food. You may feel ill without these necessary minerals if you fast for too long.
May Cause Orthostatic Hypotension
Fasting can increase the risk of orthostatic hypotension due to a sudden drop in blood pressure. Orthostatic hypotension happens when you have dizziness when you stand up.
Might Lead to Hyponatremia
Hyponatremia, when sodium levels in the blood are too low, is another risk of water fasting. This develops when you drink too much water.
Should You Try Water Fasting?
You may feel tired and have brain fog without regular food and electrolytes. Going too long without food may deprive you of essential nutrients.
You may lose weight in just a few days from water fasting, but it might not be fat loss. Any weight loss could be water weight or even the loss of lean muscle mass.
Talk to a Doctor First
It’s always a good idea to discuss trying a water fast with a doctor first. Do not start a water fast until you have been cleared by a doctor if you take certain medications or have an underlying condition.
Who Should Not Fast
Water fasting may also be harmful to certain groups of people, including:
- Certain ages: It’s not recommended to undergo a water fast if you are younger than 18 or older than 65.
- Chronic kidney disease (CKD): People with CKD are normally advised not to fast, as it may worsen the function of their kidneys.
- Diabetes: People with type 1 diabetes are advised not to water fast. Always speak with a doctor before fasting if you have type 2 diabetes. There’s a risk of hypoglycemia (low blood sugar).
- Eating disorders: People with a history of eating disorders are encouraged not to fast. Water fasting may lead to more disordered eating.
- Pregnancy or breastfeeding: Nutritional and caloric needs increase when you are pregnant or breastfeeding. Fasting is not recommended for anyone pregnant or breastfeeding.