Water Fasting Weight Loss Calculator

The weight loss associated with a water fast have three main contributing factors: gender, weight, and the duration of the water fast itself. If you’re considering going on a water fast and curious what potential weight loss you might experience, you can try our Water Fasting Weight Loss Calculator below:

Research has shown that the percentage of average weight loss was found to be slightly larger in men than in women.

Tips On the Water Fasting Weight Loss Calculator

The results produced by this calculator are approximations and vary from person to person. Please consult your local medical professional for advice.

To be able to use the Water Fasting Weight Loss Calculator effectively in conjunction with your actual water fasting, you should be re-checking your approximate weight loss calculation weekly (every 7 days).

This is because as you fast, you will be losing weight (duh!) and that means your starting weight will change. Due to the approximate nature of the calculator, there may be some inherent error associated with calculations greater than 7 days.

As an example, say you take the plunge (pun intended) and start water fasting. Your stats are:

  • Gender: MALE
  • Starting weight: 220 lbs
  • Desired fasting duration: 30 days

Entering this into the calculator, you will get a total approximate weight loss of 27.76 lbs.

However, a week into the fast, you step on a set of scales and take note of your weight as 212 lbs – a loss of 8 lbs. If we’d entered 7 days instead in our calculation above, the approximate weight loss should have been 11.2 lbs, a difference of 3.2 lbs from the actual weight loss. This means that you were losing weight slower than what the calculator estimated.

That is why we suggest re-evaluating the weight loss calculations every 7 days to decrease the discrepancies between the estimated and actual weight loss values as you progress during the fast.

How Long Can You Fast With Water?

WARNING: Anyone attempting to undertake an extended period of water fasting (longer than 72 hours) should do so under medical supervision.

There is no strict rule that says how long a water fast should last. The general rule of thumb suggests water fasting should only last for up to 72 hours – and even shorter if you’re working out during the fast. Anything longer may potentially pose some health risks such as dizziness.

However, there have been several studies that support the contrary.

One showed that going on a water-only diet for 5 days actually promotes anti-aging properties as well as decreases the risk of health conditions arising from metabolic syndrome.

Another study found that water fasting is safe for up to 8 days and anything longer may become detrimental to your health. This longer period of fasting actually demonstrated decreases in stress levels, significant weight loss, and an elevated level of ketosis.

So although our Water Fasting Weight Loss Calculator allows you to enter up to 31 days for your fasting duration, it doesn’t mean you should actually fast for that long. It’s merely an indicator to show you what’s possible. Again, we cannot stress enough how important it is to seek a medical professional for advice if you’re looking to fast for longer than a week.

Share your love
Avatar photo
Mike Julom

Mike is an ACE Certified PT and a CrossFit Level 1 Trainer. He is an avid lover of all sports. Basketball, tennis, athletics, volleyball, soccer, squash, golf, table tennis, even darts, you name it! He's a very active CrossFit athlete and has been WOD'ing for over 7 years. With such an intense fitness regime, Mike has learned to take care of his body physically, nutritionally, and spiritually. Mike founded ThisIsWhyImFit as a way to share his vast knowledge of exercises, diets, and general fitness advice.

Newsletter Updates

Enter your email address below to subscribe to our newsletter

Leave a Reply

Your email address will not be published.