Will Magnesium Break a Fast?

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Intermittent fasting has a lot of health benefits. But sometimes you need a little boost in the form of supplements. After all, you’re skipping 1-2 meals a day, so your chances of getting all your nutrients from food alone reduce drastically. But are all supplements ok while fasting, and will magnesium break a fast?

The answer depends mostly on the rules of your fasting method. It is rare, but some fasting methods require that you abstain from any type of nutrients, supplements included. Most of the time, however, it is more about the calories and especially the carbs you consume. Usually, magnesium supplements don’t have any calories, so they won’t break a fast.

Let’s take a closer look at how magnesium may impact intermittent fasting and what you should watch out for when taking it.


Will magnesium break a fast?

If your fasting method forbids you from getting any types of nutrients then yes, magnesium will break a fast. However, in most methods, the interest falls on the number of calories and carbs you consume. In other words, magnesium will not break a fast as it will not cause an insulin response.

One thing you need to consider though is the type of supplement you’re taking. Some magnesium supplements come in powdered form, which is great, except they may contain artificial flavors or even sweeteners. If you’re taking such a supplement, make sure you read the label. If there are any extra ingredients besides magnesium, think twice before using it during a fast.


Does magnesium make fasting easier?

magnesium hands

Since it doesn’t have any calories, magnesium won’t impact your appetite or your blood sugar. So if you’re having a hard time fasting because you’re constantly feeling hungry, magnesium won’t make any difference.

However, magnesium does help you while fasting. During a long fast, 16 hours or more, you’re at risk for developing an electrolyte deficiency. And if you work out during your fast, the risk increases even more. Supplementing with magnesium in this instance is not only good, it is actually recommended. That’s because it will contribute to your electrolyte balance, helping you stay hydrated and even increasing energy.

Magnesium is also great for those who suffer from anxiety or those who are going through a lot of stress. As healthy as it is for most people, intermittent fasting, abstaining from food, can put a lot of stress on your body. It can increase cortisol levels and you may find yourself restless, unable to fall asleep or relax in general. Magnesium may be just what you need in this case. This mineral helps fight fatigue, headaches, aids sleep, and may even lessen anxiety.

Finally, if you find you’re suffering from cramps, related or not to your workout, you might be suffering from a magnesium deficiency. In other words, if muscle cramps are making it harder for you to work out or if the slow down post-workout recovery, supplementing with magnesium could help.


Should you take magnesium on an empty stomach?

The answer depends on each individual. That’s because magnesium can be hard to digest and absorb for some people. If this is you, you’ll find yourself with symptoms of gastrointestinal distress such as cramps, diarrhea, nausea, headaches, sweating, bloating and more. The risk of developing such issues is greater when taking it on an empty stomach.

To find the right answer for your body, start by taking magnesium after a meal for a few days. The risk of side effects is greater with prolonged use, but also with higher doses. If, after a few days, you find you’re ok, you can try taking it on an empty stomach. In case you get any side effects at this point, you need to go back to taking it after a meal or even take a break for a few days, depending on the severity of the symptoms. Should you try to take it on an empty stomach again? That’s up to you. Do you think there’s a chance your dose was too high? Could you try to lower it? If yes, you can try doing that, but only after all the gastrointestinal issues went away.


Are there other side effects to taking magnesium?

Side effects other than digestive issues are rare when it comes to magnesium and are usually only seen in those taking very high doses.



One of the known side effects is lethargy. For most people, the fact that it promotes relaxation is one of the benefits of magnesium. But for some people, or in high doses, this positive effect can turn to lethargy. This is especially important to keep in mind if you’re taking it in the morning, in a fasted state. Your body will absorb the magnesium quicker and better. While that’s usually a good thing, it could also make you more prone to a side effect like lethargy. For this reason, it might be best to start with a lower dose to assess the effects it has on your body.


Muscle twitching

High doses of magnesium can also lead to muscle twitching. This is a rather interesting fact, considering that muscle cramps and even twitching can be a sign you are deficient in magnesium. It is yet another reason to start with a lower dose to test your tolerance, especially if you’re taking it on an empty stomach.


Irregular heartbeat

Did you know that magnesium is good for cardiovascular health? Just like with all the other benefits, this one can turn into a side effect if your dose is too high. How? You may find yourself experiencing an irregular heartbeat. That’s because magnesium is a mineral responsible for maintaining a regular heartbeat and affects the circulatory system. Too much magnesium can throw your body off balance giving you the opposite effect of what you want.


The bottom line

Will magnesium break a fast? No, magnesium is a mineral essential to the human body and most supplements do not have any calories. If you’re doing a very strict fast, such as a religious one, that allows no nutrients, supplements may be forbidden. In all other cases, you can have magnesium during your fast. Be mindful that this amazing mineral can come with certain side effects, especially gastrointestinal issues that could be exacerbated when you take it on an empty stomach.


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