48 Vs 72 Hour Fast: Which Is Better And Why?

Fasting has incredibly powerful benefits on the body – from weight loss and delayed cell aging to improved mental function and lower risk of heart disease.

In this article, we'll take a look at all the benefits of fasting, what happens physically and mentally during the different phases and durations of fasting, as well as common mistakes to avoid.

What is Fasting?

Firstly, fasting and starvation are two very different things.

Fasting is choosing to go without food for an extended amount of time. It's completely voluntary and can be ended at any time.

People use fasting as a powerful tool to prevent diseases like cancer and diabetes, promote weight loss and detoxification, and increase cognitive function.

Think of fasting as going for a long run – it's recreational, although it's not easy.

On the other hand, starvation can be thought of as needing to run for your life from some sort of danger. Starvation is a result of dire circumstances, like famine and war.

Extended fasting comes with numerous health benefits, which we'll look at below!

Benefits of Fasting

Stimulating autophagy

Fasting is believed to trigger autophagy.

This is your body's process of breaking down and recycling old, damaged cells. And in turn, replacing them with new or healthier cells.

Regulating blood glucose levels

A great way to balance your blood sugar levels is through fasting. It can also decrease insulin resistance, enhance metabolism and boost weight loss.

Improving cholesterol

An extended fast can lower your risk for cardiovascular diseases like atherosclerosis, as it's been proven to increase HDL cholesterol (“good cholesterol”) and dramatically decrease triglycerides (“bad cholesterol”).

Repairing DNA

Fasting has the potential to repair and prevent DNA damage.

According to studies on both young and aged mice, fasting dramatically improved their stem cells' ability to regenerate.

The stress of fasting results in cells breaking down fatty acids instead of glucose, which stimulates stem cells to adapt and become more regenerative.

Improving heart health

Intermittent fasting has been proven to lower chronic inflammation and improve heart health markers.

This is very promising, as inflammation can lead to damaged blood vessels, high blood pressure, and an increased risk for heart disease, heart attacks, and strokes.

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Boosting immune system

Fasting is excellent for strengthening your body's defensive mechanisms.

By regenerating stem cells and improving the rate at which damaged tissues rebuild, your recovery time after an injury or illness naturally increases too.

Reducing insulin sensitivity

Fasting is highly effective at regulating blood glucose levels which results in lower insulin levels.

Research on individuals with type 2 diabetes has shown that prolonged fasting is linked to increased insulin sensitivity, attributed to the regulation of blood sugar levels in the body.

Those with diabetes or other medical issues should always consult a medical professional before fasting.

Promoting longevity

Regular fasting throughout the year can be a powerful tool for promoting longevity, slowing down aging, and decreasing the risk for disease.

Increasing weight loss

When compared to conventional diets or restricting calories, intermittent fasting has been shown to be one of the most effective ways to lose weight.

Improving cognitive function

Fasting has the ability to clear brain fog, increase focus and alertness, improve memory, and enhance learning capabilities.

Most people who fast report thinking clearer and having improved moods.

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The Different Stages of Fasting: What To Expect

12 hours in – Ketosis

The first stage of fasting takes place about 12 to 18 hours since your last meal, once your body has used up most of its available carbs for fuel. It then begins to burn fat for energy, as well as proteins.

This process (a.k.a ketosis) involves a large number of fats being released into your bloodstream, which is converted into a fuel called ketones.

Those following a keto diet typically use fasting as a tool to kickstart ketosis.

You will likely feel the most hungry after the first few hours of fasting because your body is used to having constant access to food.

18 hours in – Fat-burning mode

After 18 hours of fasting, your body will be using ketones as your primary source of fuel, therefore burning fat.

This is the phase when people usually begin to feel insane mental clarity, increased focus, and a boost of energy.

On the other hand, others experience more difficulty focusing, brain fog, or what is known as a “fasting headache”.

Your brain would normally get its fuel from glucose, but by this time, your liver will be producing ketones for your brain to use as energy.

24 hours in – Autophagy

One to two full days into your fasting journey is when autophagy is at its peak.

This process is highly effective in improving overall health and wellbeing. It breaks down and recycles cellular material like amino acids to make new proteins and mitochondria (the powerhouse of a cell), making new energy for your cells.

Autophagy also removes damaged or defective proteins in your cells, preventing them from accumulating and leading to serious health conditions like cancer or Parkinson's disease.

A key sign of autophagy is reduced hunger levels.

48 hours in – Increased growth hormone

48 to 54 hours after last eating, there's a significant increase in human growth hormone (HGH) and noradrenaline in the body.

Both of these hormones play a huge role in speeding up the repair process of damaged cells, aiding in the prevention of health conditions like diabetes, heart attacks, and strokes.

Studies have shown that around the 3-day fasting mark, HGH increases by more than 300%!

Increased levels of these hormones have been linked to higher energy and a sense of wellbeing.

72 hours in – Cell regeneration

After 3 full days of fasting, stem cell regeneration takes place, creating new white blood cells which completely renew the immune system.

Studies have shown that this process is highly beneficial specifically for cancer patients, as a 72-hour fast can mitigate some of the harmful effects of chemotherapy.

All the previous benefits (autophagy, the increase in the production of beneficial hormones and chemicals, fat burning, and mental function) continue to increase.

Common Mistakes to Avoid While Fasting

Being too extreme in the beginning

If you have never tried fasting before, diving right into an extreme fasting program can be extremely challenging and might be too much of a shock to your body.

It's important to set realistic goals for yourself, as you're likely to give up or find the process too overwhelming if you don't build it up.

The best way to ease into extended fasting is by starting off with intermittent fasting for short periods of time.

For example, fasting for 16 hours and then eating in an 8-hour window. This will help you to prepare physically and mentally for longer, harder fasts.

Not staying hydrated

Since you will only be allowed to drink water and zero-calorie fluids during your fast, it's essential that you drink enough throughout the whole duration to avoid dehydration.

You may find that your body starts to need even more water during the fast, as glycogen (which holds water) will be used up, and you won't be retaining fluids as usual.

Besides staying hydrated, drinking fluids regularly is key to maintaining your electrolyte balance. Adding a pinch of salt to your water also helps with this.

You can also take approved supplements for fasting, like multivitamins or electrolytes, to help with the process.

Breaking your fast with the wrong foods

Although it seems like the ideal thing to do, a huge mistake you could make after a long fast is to feast.

If you haven't consumed food for 2 to 3 days, you'll need to reintroduce foods carefully to avoid digestive issues.

The rule of thumb is to take the number of fasting days and divide it by 2. That'll be the number of days you will need to be mindful of what and how much you eat.

For instance, after a 72-hour fast, you'll need to take 1.5 days to eat meals of low fiber foods (like soup and bone broth) and build up your tolerance before resuming your normal routine of eating solid food.

Not knowing when to stop

Yes, extensive fasting comes with incredible health benefits, but being too extreme and extending your fast for too long can actually cause more harm than good.

Fasting can be stressful for the body, so it's best to only practice 48 to 72-hour fasts every two to three months.

If you go without food for too long or too often, it can lead to severe mineral and vitamin deficiencies.

Who Shouldn't do Extended Fasting?

Both men and women have been practicing fasting since ancient times, for both health and spiritual reasons.

However, fasting can be detrimental to certain groups of people:

• Pregnant and breastfeeding women – as they require higher than normal nutrient levels to nurture themselves and their babies.
• Those with a history of eating disorders, like anorexia or bulimia – as fasting may trigger these tendencies.
• Anyone who is malnourished – or with a BMI lower than 18.5.
• People on medication – for example, insulin or blood pressure medicines. They would need to be supervised by a doctor.

FAQs

Does fasting cause muscle loss?

According to studies, fasting does not cause muscle breakdown if regular exercise is maintained.

In fact, fasting can have the opposite effect since growth hormone levels increase drastically, which naturally enhances muscle building and strength.

Many bodybuilders and athletes practice fasting and timed eating to increase muscle mass and reduce body fat.

What are the best foods to break a fast?

The foods you eat after your fasting period are extremely important for ensuring you don't overload your digestive system.

Will fasting slow down your metabolism?

The myth that fasting slows down your metabolism has long been busted.

Human studies performed on participants practicing a 4-day fast found that their metabolisms were increased by as much as 12%!

How often should you do a 72-hour fast?

The answer to this question will be different for everyone, as the safety of fasting for 72 hours will vary according to different factors, including the individual's overall health.

Experts in health and nutrition recommend practicing a 72-hour fast 2 to 3 times a year to strengthen your body's immune response through stem-cell regeneration and therefore prevent chronic disease.

48 Vs 72 Hour Fast: Conclusion

In general, fasting is incredibly good for your health and wellbeing.

The big question is: Is it better to do a 48-hour fast or a 72-hour fast?

Well, it entirely depends on your current state of health, your experience with fasting, and how your body responds to going without food for long periods of time.

It's always best to start out small. Consider beginning with an intermittent fasting protocol (like 16/8), then move on to a 2-day fast, before attempting a full 4-day fast.

If you're thinking about doing a prolonged fast and you deem yourself fit – give it a go! Even if it's just once per year, your body will thank you.

And once you feel the physical and mental benefits, you'll likely want to make it part of your lifestyle!