Water Fasting: What Are the Benefits and Dangers?

by Matt Weik, BS, CSCS, CPT, CSN

Water fasting is a practice that has gained popularity in recent years, with some people claiming it has helped them lose weight, detoxify their bodies, and improve their overall health. However, as with any fasting, it’s important to understand both the potential benefits as well as the risks involved.

Jumping on the bandwagon of the popularity of intermittent fasting, water fasting is making waves in the diet world once again. This approach is not new, as it dates back to ancient Greece, with minimum scientific evidence, although many naturopathic doctors tout its potential benefits.

In this article, we are going to dive deeper and examine the potential benefits and dangers of water fasting, providing you with the information you need to make an informed decision about whether this practice is right for you.

Disclaimer: This article is for informational purposes only and is not meant to treat or diagnose any condition. It is recommended that you speak with your doctor before changing your nutrition or workout program.

What is Water Fasting?

Water fasting involves consuming only water for a period of 24-72 hours, mainly for religious, weight loss, detox, or health reasons.

Studies suggest that water fasting can lower the risk of certain diseases and promote autophagy, the process of breaking down and recycling old parts of cells and promoting new cellular growth and improved health. However, following a water fast for an extended period without medical supervision can be dangerous.

The lemon detox cleanses a popular diet modeled after the water fast, but it also has limitations.

What are the Health Benefits of Water Fasting?

The health benefits of water fasting refer to the methods by which it can help an individual’s physical health and includes the following benefits.

1.      Lowers blood pressure

Research suggests that water fasting can provide health benefits such as lower systolic blood pressure, improved levels of LDL cholesterol, and reduced inflammation. For example, a study of 48 people who were overweight or obese showed that doing water fasting for an average of around 17 days under medical management led to these improvements.

Another review also found that water fasting can reduce blood pressure and body weight in people with hypertension. However, more research is needed to understand the relationship between short-term water fasts and blood pressure.

2.      It may promote autophagy

Autophagy is a process in which the old parts of our body cells are broken down and recycled. Many animal studies suggest that autophagy may help protect against cancer and other diseases such as Alzheimer’s and heart disease.

For instance, autophagy may prevent broken parts of your cells from accumulating, which is a risk factor for various types of cancers. This may help prevent cancer cells from multiplying. Animal studies have consistently found that water fasting helps boost autophagy.

3.      Regulation of hunger hormones

Hunger hormones such as ghrelin and leptin play an essential role in regulating appetite and fullness. Leptin, in particular, controls feelings of fullness, but some individuals may experience leptin resistance, which can affect their ability to feel satisfied with their food intake.

Although some studies suggest that water fasting can help regulate leptin levels, the impact of fasting on leptin sensitivity is still uncertain. Fasting may affect leptin levels in different ways depending on the duration of the fast and the individual’s metabolism.

Water Fasting and Weight Loss

While water fasting may result in weight loss, it’s not the most sustainable or healthy option. Severely restricting food intake can affect your hunger hormones and lead to weight regain once you resume normal eating habits.

Instead, making gradual lifestyle changes that you can maintain over the long term is a better approach to weight loss. The slow and steady progress of 1 to 2 pounds per week is a safe and sustainable rate of weight loss.

If you’re determined to try water fasting for weight loss, it’s better to opt for safer and less extreme methods that won’t compromise your health. Small lifestyle changes are preferable to drastic diets like intermittent fasting or keto.

Potential Risks of Water Fasting

Water fasting can have potential risks, especially if done for an extended period without medical supervision. Below are some of the potential risks of water fasting.

  • Dehydration: Not consuming enough fluids can cause dehydration, which can lead to dizziness, fainting, and electrolyte imbalances.
  • Nutrient deficiencies: Water fasting can lead to nutrient deficiencies, as you are not consuming any food or supplements. This can cause weakness, fatigue, and a weakened immune system.
  • Muscle loss: Water fasting can cause muscle loss, which can lead to a slower metabolism and difficulty in maintaining weight loss.
  • Eating disorders: People with a history of eating disorders may find water fasting triggers disordered eating patterns.
  • Adverse health effects: Water fasting can lead to adverse health effects, including headaches, nausea, vomiting, low blood sugar, and irregular heart rhythms.