Electrolytes for fasting and a keto diet
- Susanne W Smith
- Apr 15, 2024
- 3 min read
Updated: May 30
Electrolytes for fasting and a keto diet: Why they matter more than you think
If you're following a ketogenic or low-carb lifestyle—or diving into fasting—you’ve probably felt amazing... until you didn’t.
That sudden fatigue, brain fog, dizziness, or cramping? It’s likely not the diet. It’s an electrolyte imbalance.
The truth is, electrolytes can make or break your experience. In fact, failing to replenish them is one of the top reasons people quit fasting or keto too soon, thinking, “This just isn’t for me.”
But once you understand how electrolytes work—and how to keep them in balance—you’ll feel energised, focused, and on track.
What are electrolytes?
Electrolytes are essential minerals your body needs to function properly. They regulate hydration, nerve signaling, muscle contractions, heart rhythm, and more. The main ones to focus on during fasting and keto are:
Sodium
Magnesium
Potassium
When you cut carbs or start fasting, your insulin levels drop—and that triggers your kidneys to flush out water and electrolytes. Without proper replenishment, you may experience symptoms that make you feel like your body is "crashing."
Let’s break it down.
Sodium
Why it's critical:
Sodium helps maintain fluid balance, nerve function, blood pressure, and muscle performance.
Signs you're low on sodium:
Fatigue
Weakness
Nausea
Headaches
Brain fog
Dizziness (especially when standing up)
How to replenish:
Mix ½–1 tsp of unrefined sea salt (I recommend Celtic sea salt) in a glass of water. Sip slowly. This is especially important during extended fasts or after a sweaty workout.
Magnesium
Why it's critical:
Magnesium supports muscle and nerve function, sleep, digestion, heart health, blood sugar regulation—and can help reduce anxiety.
Signs you're low on magnesium:
Muscle cramps
Twitching
Restless legs
Poor sleep
How to replenish:
Take magnesium glycinate, ideally in powder form mixed with water. If in capsule form, open it and dissolve in water if safe to do so. Take it about an hour before bedtime.
Magnesium-rich foods (for your eating window):
Avocado
Spinach
Nuts and seeds
Dark chocolate
Wild-caught fatty fish
Chicken
Potassium
Why it's critical:
Potassium keeps your heart rhythm steady, supports muscle contractions, and helps prevent brain fog.
Signs you're low on potassium:
Heart palpitations
Muscle cramps or twitches
Brain fog
How to replenish:
Eat more potassium-rich foods during your eating window.
Potassium-rich foods:
Avocado
Mushrooms
Brussels sprouts
Spinach
Swiss chard
Wild-caught salmon
My Advice: Don’t Make the Mistakes I Did
When I first started fasting and keto, I underestimated the power of electrolytes. I thought I could tough it out. But what I really needed was salt, magnesium, and potassium.
Once I started supplementing properly, everything changed. My energy improved, the fog lifted, and fasting became something I actually enjoyed.
If you’re new to fasting or keto, don’t skip this step. It’s not optional—it’s essential.
Final Thoughts
Whether you're doing intermittent fasting, extended fasting, or eating low-carb/keto, electrolyte balance is key to feeling good and staying consistent.
Start smart. Supplement wisely. And remember—this lifestyle can feel amazing... when your minerals are in check.
Need Support? Let’s Do This Together.
Starting a fasting or keto lifestyle can feel overwhelming—especially when you're trying to figure it all out on your own. If you’re tired of the guesswork and want to avoid common (and costly) mistakes, I’m here to help.
With 1-to-1 coaching, you'll get personalised support, guidance, and a clear plan that works for your body and lifestyle. We’ll tackle everything from electrolytes and fasting schedules to mindset and meal planning—so you can feel confident, empowered, and in control of your health.
Ready to feel better, faster—and skip the trial and error?
Let’s work together! Fasting and Healing 1-to-1 coaching
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