​24-Hour Fasting for Weight Loss – Is It Safe?

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Fasting has become quite popular over the last few years among the health and fitness community and many of you may be wondering about 24-hour fasting for weight loss: Is it safe?

While trends constantly change in the dieting and weight loss world, fasting is one component of a healthy lifestyle that recurs in different forms. Intermittent fasting, juice diets, and cleanses are just a few of the many.

By recurring, we mean that philosophers and religious cultures have been fasting for health and spiritual reasons for thousands of years. So don’t worry

Plenty of doctors, nutritionists, and other health experts tout the benefits of fasting, including improved brain function, reduction in stress levels, improved immune system, and even weight loss (when used correctly).

Guys, before we dive into the goods in this article, we just want to say a couple of words about our experience with fasting.

We have done intermittent fasting and 24-hour fasts on and off over the last year and with so much success that it has become a part of our popular fast weight loss program, the 21-Day Fat Loss Challenge.

It’s nothing to be afraid of and something that you should never knock it until you try it! This is how I first felt about it (a little scared and concerned), but after diving into the research more and trying it myself, I absolutely love it!

I find that I like intermittent fasting better (pushing back breakfast until closer to lunchtime), but the occasional 24-hour fast is also a great way to detox and reset your system.

Our clients especially love the 24-hour fasts after a vacation or a night out with friends when they overindulged just a little too much.

Just keep all of this in mind as you are reading this article!

Whether your reasons are for detox purposes, to wean yourself off processed foods and sugars, for religious or spiritual reasons, or for weight loss, this article on the science and safety of fasting should help you get your mind right about it!

Is 24-hour fasting a fad or a legitimate and safe method of weight loss?

We’ll discuss the bodies of research that cover this controversial topic here and share what we’ve learned about 24-hour fasting.

What is 24-hour fasting?

A 24-hour fast, also known as an intermittent fast, is fast becoming a popular weight loss method for people who have hit plateaus in their weight loss journeys.

According to NPR’s article on the subject, partial fasts retune the body and suppress insulin secretion. Their endocrinologist expert also notes that fasting can reduce your taste for sugary treats.

She also says that letting your body burn up the sugars it’s already holding onto can give your pancreas a break from creating insulin. Conversely, in juice fasts, your pancreas is still working against sugars.

Also, fasting doesn’t involve the byproducts that eating food does. When we consume food, we don’t just consume energy, but free radicals and other components too.

As far as safety goes, a research article by Roger Collier states that it becomes unsafe (even dangerous) when people do it incorrectly.

The problem lies in people’s tendency to think that when they fast, that resets their system and allows them to continue to consume junk food outside the fasting period.

While that isn’t healthy, it’s also dangerous, because depriving your body of vital nutrients before or after a fast can hamper the body’s ability to use what you’re putting into it.

It’s important to note that everyone fasts every day (intermittent fasting), especially those who have their last meal before bed and don’t eat again until breakfast. You are fasting naturally while you are sleeping.

Precision Nutrition’s article on the benefits of intermittent fasting uses this model to explain that fasting is a natural part of our body’s balance.

Our regular sleep schedules and eating habits put us on a 12 hour or so fast each night while we sleep. This is a normal bodily function with healthy side effects, so wouldn’t it make sense that there might be some additional health benefits from extending this period of fasting?

What are the benefits?

There are many benefits of fasting that we have laid out in full detail in our post on the 11 Proven Benefits of Fasting.

Fasting can…

  • Help you lose weight
  • Enhance your body’s resistance to stress
  • Help prevent cancer
  • Improve brain function
  • Improve your immune system
  • Increase your life span
  • Raise growth hormone levels
  • Maintain lean muscle tissue
  • And more!

Please check out the article for more benefits + the scientific studies backing up the points above.

How does a fast work?

When implementing a fast, it’s best to choose a day when you are on your own schedule in case you experience fatigue or other side effects. Consume plenty of water to prevent dehydration, and don’t overexert yourself.

ice water for weight loss

What seems to work best for our clients on our 21-Day Fat Loss Challenge is to fast on a day when you can keep yourself busy. A day full of errands is perfect because it will keep your mind off of food.

Boredom is your enemy during fasting because your mind will try to convince you that you are hungrier than you are when it wants to eat out of boredom!

It’s important to note that for a full 24-hour fast, you will never go sun-up to sun-down without eating. This is a common misconception that causes most to initially balk at the idea of a ’24-hour fast.’

The best time to start your fast is after dinner (say 7 pm), and then don’t eat again until dinner the following evening (7 pm). This way, you are sleeping off a large portion of the fast!

In general, fasting means not consuming anything but water. But it’s okay to consume black coffee and tea (no cream or sugar), lemon water, or water with apple cider vinegar.

You cannot consume any food during this time or any other drinks with calories that will break your fast.

Brad Pilon, an intermittent fasting guru, told Men’s Journal that fat loss starts at about hour 12 to 13 of a fast, and reaches a plateau around 16 hours. This follows the 24-hour fast model closely.

Learn more about Brad’s intermittent fasting plan in his video below, which discusses one way to use intermittent fasting in your fitness pursuits.

Easing into meals after fasting is also imperative so that you don’t overindulge or make yourself sick with excess sugar or carbohydrates.

Is 24-hour fasting safe?

Well, we’ve already explained all of the benefits above! Still not convinced?

Although it’s not without side effects, it’s definitely safe. Let us explain…

When fasting long-term, NPR’s experts note, there is the potential for toxic proteins to release into the body. This happens due to the body entering starvation mode, which means it’s burning muscle.

Fat burning happens at different rates for different bodies, so it’s important to stay vigilant when fasting, or you may enter starvation mode or experience dizziness or other negative symptoms.

An additional note made by Precision Nutrition’s article is that the perceived benefits of fasting may show up as a result of more normal eating behaviors.

For example, controlled calorie studies tend to show improvement in overall health and body composition with lowered calorie intake.

If we combine periodic fasting with our normal calorie intake, this balances out our calorie consumption to where we’re burning more than we’re eating.

Overall, lowering your caloric intake may be the best bet for spurring weight loss and sculpting your body, but incorporating fasting with healthy food intake is absolutely safe.

Guys, if you want to try out fasting in your life in a safe and controlled manner, I encourage you to grab a copy of our 21-Day Fat Loss Challenge Program.

We incorporate both the intermittent fasting and the 24-hour fasts in the program, but they are also totally optional! So you can give it a shot if you want, and if you find that it’s not for you, there are other options as well!

This is what Selene had to say in our private support group for the Challenge:

Selene 21-Day Challenge testimonial on fasting for weight loss

On this program, our clients lose an average of 10-21 pounds in 21 days and absolutely love it!  But even better than the weight loss is the feedback we get from people about how the program has taught them how to change their eating habits and find a diet that truly works for them in the long-term.

Avocadu 21-Day Fat Loss Challenge

We have over 2,000 Challenge members in our private support group going through the program together, and every day they are sharing experiences, results, motivation, and lots of recipes!

If you are ready to make some changes in your life, we will teach you exactly how to make the necessary changes in your diet and your lifestyle and how to keep them “beyond the diet.”

Click here to get started with your 21-Day Fat Loss Challenge!

If you enjoyed this article on 24-hour fasting for weight loss or have any questions for us, please leave them in the comment section below!


  1. Good article.I really love your post, thanks for sharing this and looking forward to seeing more from weight loss article.

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