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Benefits Of A 24-Hour Fast Once A Week: Is It Right For You?
Updated on
- Written by McCall Breuer, CNM, WHNP-BC
Medically reviewed by
Brittany Ferri, Ph.D.
Fasting has become a popular approach to health management, whether for weight loss, reducing the risk of chronic disease, or both. In fact, this practice is very old, reaching back far into human history as a physical and spiritual discipline. There is a lot of seemingly contradictory information floating around about fasting, and it can be hard to figure out what the real benefits and risks are. In this article, we’ll discuss the evidence about the short- and long-term health effects of fasting, the potential risks and side effects, and how to break your fast.
4 Benefits Of 24-Hour Fast Once a Week
- Weight loss
- Reduced inflammation
- Improve cardiovascular health
- Improve brain health
Is 24-Hour Fast Good for Weight Loss?
At first, it may sound like fasting is a great solution for weight loss since it inherently involves calorie restriction. And many people indeed lose body fat when they employ intermittent fasting. This happens because, as blood glucose declines in the fasting state, the body secretes less insulin, which in turn triggers the breakdown of fat[1] to make energy for cells.
But there are possible downsides to relying on fasting to lose weight. One of the reasons is that fasting can be a very challenging eating pattern to maintain. While some people may lose weight on an intermittent 24-hour fasting diet, they may also have trouble maintaining that loss for the long term, which is all-important when it comes to the health benefits of weight loss.
What Is The 24-hour Fast?
The 24-hour fast is a subtype of intermittent fasting in which you abstain from all food for 24 hours. This type of fast is also known as “Eat Stop Eat” due to the way eating bookends the period of fasting. It is considered a kind of time-restricted fasting because it limits your fasting to a specific time frame.
The 24-hour fast differs from the popular 16/8 fast (in which you fast for 16 hours and eat during the remaining 8 hours of a 24-hour period) because you typically do it fewer times per week. In its strictest form, it also differs from other kinds of fasting that allow for a small calorie intake (think 500 or so calories) on fasting days.
Benefits Of 24-Hour Fast Once A Week
Weight loss
So how does 24-hour fasting compare with other weight loss strategies? Overall, it appears that fasting on alternate days is comparable to other calorie-restriction diets[2] for weight loss. This makes sense given what we know about how the body utilizes stored energy in fat when in a low-insulin state. This helps with both weight and blood sugar control.
But is fasting superior to other approaches for weight loss? The jury is still out[3] on that question.
More evidence is needed to understand if a 24-hour fast will get you closer to your weight loss goals than other ways of eating fewer calories.
Reduced inflammation
One thing that seems fairly certain[4] from the research on intermittent fasting is its effect on inflammatory markers. These are the chemicals that show how much inflammation you have in your body, and fasting can lower the number of these markers.
Why do we care about inflammation? It turns out that chronic inflammation underlies many chronic diseases[5]. This includes metabolic disorders such as diabetes, cardiovascular disease, arthritis, and even neurodegenerative diseases. So it may be that doing the occasional 24-hour fast can reduce your risk of these inflammation-mediated conditions, raising your chances not only for a longer life but a healthier one, too.
Improve cardiovascular health
Lower blood glucose and reduced overall inflammation have a surprising downstream effect: combined, they can reduce the risk[6] of cardiovascular disease. Each of these factors means less damage to your blood vessels, including the blood vessels on your heart, called the coronary arteries. Keeping your vessels healthy and flexible is critical to health, and fasting may help.
Excitingly, the benefits of fasting on cardiovascular health can even be had by those who already have cardiovascular diseases, such as heart failure or coronary artery disease. Studies[7] have shown that people who fasted for religious reasons after a cardiovascular diagnosis went on to have reduced incidence of recurrence.
There are confounding variables when it comes to the benefits of fasting for heart health. Namely, is fasting itself good for your heart, blood pressure, and lipids? Or is lower body weight the risk reducer? Right now, it’s still too early to tell[8]. But talk to your doctor about a fasting diet if you think it could be part of your overall health plan.
Improve brain health
We’ve covered your weight, your heart, and your inflammatory blood markers. What about your brain? Neurological aging and degeneration are important causes of disability, and it’s important to protect your brain health just as much as it is the rest of your body.
Some studies have indicated that fasting regimens may improve verbal memory[9] in adults. Although more research is needed in this area, it stands to reason that the anti-inflammatory benefits we know come from fasting could also benefit the brain[10], which is vulnerable to stress from inflammation.
Side Effects and Risks
In most cases, the side effects of fasting are fairly benign. You might feel bad from the lack of food – think weakness, irritability, and headaches. This is likely due to low blood sugar, but if you are otherwise healthy, your blood sugar is unlikely to go dangerously low.
Another common side effect is rebound overeating[11]. This occurs when you are so hungry following a fast that you eat a lot of food during your non-fasting times. This can be uncomfortable in the short-term, and potentially detrimental to your weight loss or other health goals in the long term. Keep reading for information about what to eat after a fasting period.
Are there any serious health risks to a 24-hour fast? There may be for certain groups. Fasting carries an inherent risk of low blood sugar, and you may be especially vulnerable to this if you are on blood sugar-lowering medications for diabetes. Fasting also impacts your electrolytes, which can be dangerous for people with certain heart conditions or on specific medications. And finally, if you have any history of eating disorders, fasting may not be the right choice for you.
How Often Should You Do a 24-Hour Fast?
A true 24-hour fast involves abstaining from all food. As such, you only need to do it about once per week. This is in part because the side effects of a 24-hour fast can be pronounced[12]. Less intense forms of fasting that allow for a small amount of calorie intake may be more reasonable to do one to two times per week. You can always start with this lighter kind of fasting and ramp up to a 24-hour fast, which may ease your transition into fasting.
What Should You Eat After a 24-Hour Fast?
It’s very important to eat a balanced diet and eat at regular times on days you are not fasting to ensure your body gets all the nutrients it needs. Pairing your fasting routine with a healthy, anti-inflammatory diet such as the Mediterranean diet on your days off can only stand to improve your overall health[13].
Trying to combine fasting with another restrictive diet is probably unnecessary for your health, and may increase the risk of other nutrient deficiencies. And the same goes for other weight loss tricks like diet pills; if you’re going to use them, save them for a time when you’re not fasting regularly.
For an immediate post-fast treat, you may want to start with something hydrating and easy to digest, such as broth or a smoothie. These foods can be delicious and nourishing while simultaneously easing your body back into digestion following a long fast.
Conclusion
24-hour fasting is an emerging way of dieting that holds promise for reducing body fat, improving cellular health, and lowering the risk of chronic diseases. It’s not right for everyone, but it’s worth considering if you’re interested in these goals. Speak with your doctor about whether this diet could be a good fit for you.
Frequently Asked Questions
Not necessarily. People with certain medical conditions or on specific medications may not be the best candidates. Talk to your doctor about your history before trying this type of diet.
You will likely lose some weight, but it depends in part on your other diet and lifestyle choices, and how long you can sustain this eating pattern.
24-hour fasting may improve your lipid profile, reduce your blood pressure, bring down inflammatory markers in your blood, and even boost your brain health.
+ 13 sources
Health Canal avoids using tertiary references. We have strict sourcing guidelines and rely on peer-reviewed studies, academic researches from medical associations and institutions. To ensure the accuracy of articles in Health Canal, you can read more about the editorial process here
- Harvard (2018). Intermittent fasting: The positive news continues – Harvard Health. [online] Harvard Health. Available at: https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156.
- Mayo Clinic. (2022). Is intermittent fasting good for you? [online] Available at: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/intermittent-fasting/faq-20441303.
- Medilib.ir. (2023). Obesity in adults: Dietary therapy. [online] Available at: https://www.medilib.ir/uptodate/show/5375.
- Harvard Health. (2020). Understanding acute and chronic inflammation – Harvard Health. [online] Available at: https://www.health.harvard.edu/staying-healthy/understanding-acute-and-chronic-inflammation#:~:text=Research%20has%20shown%20that%20chronic,to%20know%20its%20exact%20impact.
- www.heart.org. (2021). Intermittent fasting may protect the heart by controlling inflammation. [online] Available at: https://www.heart.org/en/news/2021/11/18/intermittent-fasting-may-protect-the-heart-by-controlling-inflammation.
- Dong, T., Sandesara, P.B., Dhindsa, D.S., Quyyumi, A.A., Arneson, L.N., Dollar, A.L., Taub, P.R. and Sperling, L.S. (2020). Intermittent Fasting: A Heart Healthy Dietary Pattern? [online] 133(8), pp.901–907. doi:https://doi.org/10.1016/j.amjmed.2020.03.030.
- Heart (2020). Fasting: How Does It Affect Your Heart and Blood Pressure? [online] Cleveland Clinic. Available at: https://health.clevelandclinic.org/fasting-how-does-it-affect-your-heart-and-blood-pressure/.
- Heart (2020). Fasting: How Does It Affect Your Heart and Blood Pressure? [online] Cleveland Clinic. Available at: https://health.clevelandclinic.org/fasting-how-does-it-affect-your-heart-and-blood-pressure/.
- Amor, S., Puentes, F., Baker, D. and Paul (2010). Inflammation in neurodegenerative diseases. [online] 129(2), pp.154–169. doi:https://doi.org/10.1111/j.1365-2567.2009.03225.x.
- Heart (2020). Fasting: How Does It Affect Your Heart and Blood Pressure? [online] Cleveland Clinic. Available at: https://health.clevelandclinic.org/fasting-how-does-it-affect-your-heart-and-blood-pressure/.
- Harvard Health. (2020). 4 intermittent fasting side effects to watch out for – Harvard Health. [online] Available at: https://www.health.harvard.edu/staying-healthy/4-intermittent-fasting-side-effects-to-watch-out-for.
- hollowc2 (2022). Intermittent Fasting: How It Works and 4 Types Explained. [online] Cleveland Clinic. Available at: https://health.clevelandclinic.org/intermittent-fasting-4-different-types-explained/.
- Attinà A, Leggeri, C., Paroni, R., Pivari, F., Michele Dei Cas, Mingione, A., Dri, M., Marchetti, M. and Laura Di Renzo (2021). Fasting: How to Guide. [online] 13(5), pp.1570–1570. doi:https://doi.org/10.3390/nu13051570.
Written by:
McCall Breuer, CNM, WHNP-BC
Medically reviewed by:
Medically reviewed by:
