by Matt Weik, BS, CSCS, CPT, CSN
What if there was a simple weekly routine that you could easily follow that took the best of intermittent fasting and extended fasts? Something that provided all the benefits without the daily commitment and regimen you’d need to follow? That’s where a 24-hour fast solves the problem and offers a quick and easy way to experience all the benefits of fasting without the weekly commitment.
Fasting can cause a bunch of amazing physiological changes. As your body depletes its food-derived energy and glycogen stored in muscles and the liver, a transformation begins. Typically, this glycogen, about 2,000 calories worth, depletes within a 24-hour period. At this point, the body shifts from building tissue to breaking down glycogen and fat for energy.
This catabolic phase shifts your metabolism to a ketogenic state, starting autophagy, the cellular renewal process. Both of these states are associated with numerous health benefits.
In this article, we’ll dive deeper into how to go about doing a 24-hour fast, as well as all of the many benefits you can experience when doing it.
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 starting any exercise program, making changes to your nutrition plan, or adding any new supplements into your current routine.
What Happens During a 24-Hour Fast?
Skipping food for 24 hours while drinking only water or plain herbal teas is known as a 24-hour fast. Does it sound odd? Yup. Does it sound somewhat challenging and potentially uncomfortable? Perhaps. But people do this weekly, monthly, or as needed to reduce their calorie intake.
When you fast for a long time, your body starts using fat for energy. Your liver breaks down fat, creating ketones, which are used as fuel for your cells.
As your body uses more ketones, it enters ketosis. This state not only helps with weight loss but also improves overall health at the cellular level.
Without a doubt, different fasting plans have become popular lately. These include 24-hour fasts and the tried-and-true 16:8 method, where you eat only during an 8-hour window each day and fast the other 16 hours.
People like these plans because they might help control blood sugar, repair cells, and boost brain function.
A study found that a 24-hour fast could lower insulin resistance, improve fat breakdown, reduce weight and body fat, lessen depression, and enhance thinking skills.
7 Benefits of 24 hours of fasting
Here are some of the notable benefits of doing a 24-hour fast:
1. Weight loss
One of the most well-supported benefits of a 24-hour fast is weight loss. After approximately 24 hours of fasting, the body depletes its glycogen reserves, the stored form of glucose. Once glycogen is used up, the body starts burning fat for energy.
A 2015 review, which analyzed seven studies on whole-day fasting, found that individuals who followed a low-calorie diet and engaged in a 24-hour fast once or twice a week for 12 to 24 weeks saw body weight reductions of up to 9% compared to control groups.
2. Autophagy
Autophagy is an amazing thing, and extended fasting, like a 24-hour fast, triggers autophagy.
What exactly is autophagy? It’s a cellular clean-up process where healthy cells eliminate waste and dead cells. This process helps enhance cellular health, reduce inflammation, support new cell growth and may help slow the aging process.
3. Supports metabolic health
Metabolic syndrome, marked by high blood sugar and blood pressure, heightens the risk of heart disease.
A 2021 study with 103 participants found that those who did water-only 24-hour fasts twice weekly for four weeks, then once weekly for 22 weeks, saw significant reductions in their Metabolic Syndrome Score. They had better diastolic blood pressure, HDL cholesterol, blood sugar, and triglycerides, unlike the control group, which saw increased MSS scores.
4. It may help fight certain types of cancers
Though human studies are limited, animal research suggests fasting may aid in fighting certain cancers by making tumor cells more sensitive to chemotherapy. This increased sensitivity helps target and destroy tumors more effectively, especially in aggressive cancer cases.
5. It may increase human growth hormone
A weekly 24-hour fast can boost the production of human growth hormone (HGH). A classic study involving 200 participants found that fasting for 24 hours increased HGH levels by 20 times in men and 13 times in women.
Increased HGH levels are linked to better memory, increased muscle mass, reduced water retention, and lower cortisol levels, the stress hormone.
6. Increased BDNF
BDNF, or brain-derived neurotrophic factor, is a hormone that supports brain cell growth. A 24-hour fast can boost BDNF levels, which is linked to improved learning and the formation of new neural pathways.
Low BDNF levels are connected to neurodegenerative disorders like Parkinson’s and Alzheimer’s.
Research suggests that intermittent fasting can raise BDNF levels, potentially reducing depression, anxiety, and neurodegenerative diseases in animal studies.
7. It can reduce oxidative stress
A key benefit of a weekly 24-hour fast is its potential to protect your body from oxidative stress, which results from damage by free radicals and reactive species.
Oxidative stress can lead to premature protein and cellular membrane breakdown, DNA alterations, and accelerated cellular aging.