If you’ve ever tried fasting before, staring at your supplement stack can probably be pretty daunting. What will keep you in a fasted state, and what will kick you out? But if you’ve heard one piece of advice, it’s probably this: take your electrolytes—that is, magnesium, sodium, and potassium.
If you’re like most people, common advice is excellent for steering you in the right direction, but you likely have no idea why you need to take your electrolytes and what they do for your body. Here, we’re talking about one in specific: magnesium.
Magnesium is one of the essential minerals we call electrolytes, and we’re talking about why magnesium is necessary and if taking it will break a fast.
What Is Magnesium And Why Do We Need It?
Chances are you’ve heard about magnesium. Whether it’s in relation to muscle tension or bone health, magnesium is a big deal in the mineral world. It is a cofactor in more than 300 enzymatic reactions needed to stabilize enzymes, especially those involved in ATP production 1, 2.
The body requires ATP for nearly every function, ranging from glucose utilization and synthesis of fat, proteins, nucleic acids, and coenzymes to muscle contraction, vascular tone, and neurological function.
Because it’s heavily involved in many biological processes, interruption to magnesium metabolism in any capacity influences these functions 3.
But when we’re told to consume electrolytes, including magnesium, we’re talking about its role in transporting calcium and potassium ions across the cell membrane 3.
Without calcium and potassium, your muscles can’t contract properly, which is why low magnesium levels result in muscle cramps—something that many people experience during fasting.
Here’s what else you need magnesium for:
- ATP synthesis
- Muscle contraction
- Neurological function
- Neurotransmitter release
- Vascular tone
- Heart rhythm
- Bone formation
And without sufficient magnesium intake, you could be at risk of experiencing:
- Muscle twitches, tremors, and cramps
- Mood disturbances
- Weakened bones
- Fatigue
- Muscle weakness
- High blood pressure
- Arrhythmia
Can You Take Magnesium During A Fast?
The short answer: Yes—taking magnesium will not break a fast, and supplementing with electrolytes, in general, is essential when fasting.
Magnesium and other electrolytes do not contain calories, so they have nothing that will stimulate pro-growth pathways like mTOR, which is activated by glucose/insulin (carbs) or amino acids.
When mTOR is suppressed, a pathway called AMPK stays activated; AMPK is the pathway that drives many of the benefits related to fasting—lipolysis, autophagy, etc. 4.
Simply put, electrolytes or magnesium alone aren’t going to break a fast—it’s the other ingredients added to them that will.
Getting enough magnesium, sodium, potassium, and chloride is essential to prevent muscle cramps, energy dips, and headaches that often accompany fasting. These are the main symptoms of electrolyte imbalance and manifest due to increased excretion in urine 5.
Several things can deplete electrolytes, such as sweating, excessive water intake, diarrhea, low-carb or keto diets, and fasting. Most people know that your body loses electrolytes in sweat and urine/feces, but during fasting, magnesium is excreted preferentially to reserve levels of sodium and potassium—two minerals that are key for cardiac function.
During prolonged fasting, the kidneys excrete magnesium at a shockingly high rate. One study found that obese people participating in a multi-week—yes, we know multi-week fasting isn’t frequent for most people—excreted magnesium at a rate 4-5x higher than normal 6. So, the deeper into a fast you go, the more magnesium you lose and the higher the demand for supplementation.
Related Post: Does Taking Vitamins Break a Fast? - 6 Safe to Take and 4 to Avoid while Fasting
There’s no denying that magnesium and other electrolytes are essential during a fast, but you have to be mindful of what kind of magnesium you’re taking. If your magnesium supplements contain pure magnesium (and other nutrients) with no added fillers, colors, flavors, or the like, it’s safe to take during a fast.
But if your powdered or capsulated magnesium is doused with additional ingredients that have the potential to break a fast, taking it is not recommended during your fasting window.
The Optimal Dose Of Magnesium
While it may be tempting to mega-dose your electrolytes during a fast to prevent any issues, stop right there—there’s no need to go overboard.
First and foremost, load up on magnesium-rich foods like:
- Spinach, boiled
- Brown rice
- Black beans
- Pumpkin seeds
- Cashews
- Almonds
- Dark chocolate (>85% cocoa)
- Avocados
- Bananas
For supplementation, aim for around 600 mg of magnesium per day. Most people fall short of the recommended intake by about 300 mg per day; striving for a minimum of 300 mg of supplemental magnesium will help you relax during your fast and prevent headaches, muscle cramps, and other symptoms of electrolyte deficiency 7, 8.
If you think you’re skimping on magnesium in your diet, adding a good multi to your stack could be beneficial, especially like NutriGenesis Multi. Multi supplies 17+ essential vitamins and minerals for optimal body performance across all systems.
It’s enhanced with cofactors to boost nutrient absorption and utilization—all customized in gender-specific doses for hormonal balance and healthy whole-body biological performance.
References
- Swaminathan R. Magnesium metabolism and its disorders. Clin Biochem Rev. 2003;24(2):47-66.
- Saris NE, Mervaala E, Karppanen H, Khawaja JA, Lewenstam A. Magnesium. An update on physiological, clinical and analytical aspects. Clin Chim Acta. 2000;294(1-2):1-26.
- Jahnen-Dechent W, Ketteler M. Magnesium basics.Clin Kidney J. 2012;5(Suppl 1):i3-i14.
- Herzig S, Shaw RJ. AMPK: guardian of metabolism and mitochondrial homeostasis. Nat Rev Mol Cell Biol. 2018;19(2):121-135.
- Weinsier RL. Fasting--a review with emphasis on the electrolytes. Am J Med. 1971;50(2):233-240.
- Drenick EJ, Hunt IF, Swendseid ME. Magnesium depletion during prolonged fasting of obese males. J Clin Endocrinol Metab. 1969;29(10):1341-1348.
- DiNicolantonio JJ, O’Keefe JH, Wilson W. Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis (published correction appears in Open Heart. 2018 Apr 5;5(1):e000668corr1). Open Heart. 2018;5(1):e000668.
- Boyle NB, Lawton C, Dye L. The Effects of Magnesium Supplementation on Subjective Anxiety and Stress-A Systematic Review. Nutrients. 2017;9(5):429.
