Do Supplements Break a Fast?

This is a question we get a lot in the fasting world, and it’s not a question that has a clear yes or no answer. 

It’s a little more nuanced than that.

Let’s go over it. 

First things first 

When we ask, “Does this break a fast?” we need to clarify a few things:

What does break a fast mean?

Breaking a fast technically means anytime you consume something that causes an insulin response. 

What kind of fast are we talking about: fasting for weight loss, or fasting for autophagy?

Because there’s a huge difference. 

If you’re only concerned about weight loss, there’s more wiggle room.  

But if you’re after the increased autophagy, you’re going to need to be more careful. 

What kind of supplements? 

There are all kinds of different supplements, with all kinds of different ingredients. 

As for electrolytes (sodium, magnesium, and potassium), they are vital during a fast.

Electrolytes do not break the fast (assuming they don’t have dodgy ingredients), whether it’s for weight loss or autophagy. 

Always take your electrolytes. 

Fasting for weight loss

If the primary goal of your fast is for weight loss, you have a little more leeway. 

Technically, anything with calories will break a fast. 

However, leading fasting expert, Dr. Fung, advises that a small number of calories (under 50) will probably not significantly impact the fasted state. 

Some supplements do contain a few calories, but most will be negligible. 

There are other things to consider, though, such as added ingredients. 

Some supplements (even some electrolyte brands) contain dodgy ingredients that will definitely break a fast. 

Example: sweeteners. Even sweeteners that are zero calorie can still cause an insulin response. 

Always check your labels. 

Also, some supplements cannot be taken on an empty stomach.

In that case, you could do Intermittent Fasting, instead of an Extended Fast.

That way, you have an eating window each day, and you can take the supplements then.

If you are fasting for weight loss, and taking supplements, check your progress. 

If your weight loss stalls, or you’re just not getting the results you want, the supplements could be an issue. 

Fasting for autophagy

If your fasting goal is the amazing benefits of autophagy, you will need to be much more careful. 

Anything with calories or protein can hinder autophagy. 

This means some supplements will break a fast for autophagy, especially anything that has amino acids. 

That being said, there are some supplements that are thought to activate autophagy, such as vitamin D, and vitamin B12. 

Also note that autophagy is thought to peak at around 72 hours.

So if you really want to take a supplement, but also want autophagy, you could do something like rolling 72 hour fasts, then supplement in between the fasts. 

This way you’re getting maximum autophagy benefits, but also getting in some supplements. 

Weigh the benefits

The best approach is to weigh the benefits of the supplement with the impact on your fast. 

What benefit do you hope to get from the supplement? 

Is it worth the possible impact on your fast? 

And can you modify your fasting in a way that allows you to still supplement? 

Do you actually need the supplement?

Consider this: many of the benefits we sometimes take supplements for, we already get with fasting. 

Example: Probiotics. Many people take probiotics for gut health. But fasting already helps with gut health, so you don’t necessarily have to take those. 

Also, unless you’re deficient in something, we don’t always need to take supplements when we fast. 

NOTE: If your doctor has prescribed a supplement, it’s important that you follow your doctor’s instructions. Always discuss any changes with your doctor first. 

Final thoughts

The short answer is yes, depending on your goals, some supplements can indeed break a fast. 

Knowing what benefits you’re after, both with fasting and with supplements, can help you decide whether it’s worth the trade off.