Though you may not realise it, fasting is nothing unusual, it’s a part of our everyday life. If fasting is defined as the voluntary abstention from eating food, then we fast every day while we are sleeping, hence breakfast, our first meal of the day. 

However, a fast longer than the 8-14 hours between dinner and breakfast, constitutes an intention to abstain from eating that begins to have significant physical effects on the body.

 Why fast?

 Fasting has been part of human culture since ancient civilisations. All major religions fasted as part of their spiritual practices, for example the Muslim practice of dry fasting between sunrise and sunset during the month of Ramadan, or the Christian practices during Lent before Easter.

Today, many people choose to fast for other reasons: weight loss, resolving health issues, for fitness and to optimise health.  

The biology of fasting: what happens to the body during a fast?

 During fasting, levels of the hormone insulin drop, signalling the body to start using stored energy in the form of glycogen (this is glucose stored in the liver and is enough to last 24 hours)  

 Once glycogen has run out, through a process of gluconeogenesis (literally, creating new glucose) the liver manufactures new glucose to maintain energy levels in the blood.

 After 24-36 hours, the body begins to utilise stored body fat. Ketosis (which indicates a good level of fat utilisation) follows once low insulin levels stimulate lipolysis, the breakdown of fat for energy. However it’s good to know that ketosis is not a requirement for lipolysis; you can still break down fat and lose weight without being in ketosis.

 To be clear, these processes are completely natural and normal. We wouldn’t have survived as a species if we weren’t able to activate these adaptations during times of low-food availability. In fact, going without food for long stretches of time is what we’re evolved to be able to do.

However, this blog isn’t about why and how we should fast. Should you choose to undertake a fast, this will help you understand the process the body goes through while fasting and why salt is an important consideration.

What’s the role of salt during fasting?

 First things first. It’s important to know that consuming salt does not break a fast, as it contains no calories, does not spike insulin and is essential for maintaining electrolyte balance during fasting. Just because you’re not eating food, doesn’t mean you shouldn’t consume a healthy amount of salt.

 Secondly, a quick overview of just some of the reasons the body needs sodium from salt:

• It’s an essential electrolyte for nerve and muscle function
• Helps maintain blood pressure and fluid balance
• Supports adrenal function
• Facilitates glucose absorption

During a fast, lowered levels of insulin cause the body to expel excess salt and water; insulin is well known to cause salt and water retention in the kidneys. Regularly lowering insulin levels through fasting can lead to improved insulin sensitivity – your body becomes more responsive to insulin which is the opposite of insulin resistance, the root problem in Type 2 Diabetes.

What happens to sodium during a fast?

Fasting longer than 12 hours is thought to impact electrolyte levels so it’s wise to start considering your salt intake for fasts that are more than 12 hours as even within the time frame of 12 – 24 hours, symptoms of cramping, headaches and brain fog can occur.

 As shown above, during fasts of more than 24 hours, the body decreases insulin levels, leading to increased sodium excretion through urine.  Research shows sodium levels can drop significantly within the first 3-4 days of a long-term fast.  Reduced glycogen stores also release water, potentially flushing out sodium.

Without salt intake during fasting, some fasters report experiencing:

• blood pressure drops when standing
• Muscle cramps
• Fatigue and weakness
• Headaches
• Dizziness and light headedness

Top tips for salt consumption during a fast

 Here are our top 3 tips for optimising your salt intake during a fast:

1.  Stay well-hydrated by drinking enough water, however be aware of drinking too much water which can dilute your sodium levels. Read our blog on drink less water, eat more salt here. 
2. Consider optimising your hydration with electrolytes. We like Revive (South Africa) or RePowr (UK).
3. Keep a stock of clear bone or vegetable mineral broth made with a good amount of natural salt added to taste in your freezer. Bone broth is an excellent source of minerals.

Fasting is not for everyone. There are some who experience it as a counter-productive additional stressor to an already stressful life.  Others, however, have reported fasting to be useful for weight loss, improved energy and achieving optimised well-being.  

Regardless of the type of fasting you choose – time restricted, intermittent or extended -  you will benefit by adding a natural, health-giving, mineral-rich salt.

Sources: 

1. https://www.nutri-align.com/blogs/supplements/fasting-and-sodium-are-you-getting-enough?utm_source=chatgpt.com
2. aspect-health.com
3. Salt for Fasting: The Importance, Low-Sodium Symptoms ... - Aspect
4. LMNT Electrolytes
5. Benefits of sodium while fasting (And how to get enough) - Science
6.  The Complete Guide To Fasting (© 2016) Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting - Jason Fung, MD, with Jimmy Moore