Does MCT Oil Break a Fast?

If you’re fasting to improve health or weight loss you might be wondering exactly what constitutes breaking your fast – and whether certain foods class as fast breakers or not? Well, we’re going to cover them in our ‘what breaks a fast’ series – and we’ll start with a super trendy addition to many people’s morning routine – MCT oil. So let’s find out, does MCT oil break a fast?

The TL:DR Answer

The fact is, will MCT oil end a fast or not is complex.

Technically, because it contains calories, yes, it does – but, the way that MCT oil works in the body may mean that there could be fewer effects from breaking a fast with MCT oil than some other substances.

However, some people do find that consuming MCT oil or MCT oil coffee on an empty stomach does not suit their digestive system at all

To tease out whether you’re going to want to add MCT oil to your fasting regime therefore, read on …

What Constitutes a Fast?

In this piece we are only talking about fasting in regards to the protocols used in time restricted eating, and intermittent fasting, rather than any kind of religious, spiritual or medical fasting where consuming anything other than water does break the fast.

In time restricted eating the idea is that you leave a break of, somewhere between, 12 and 16 hours between your last meal of the day and your first the next day. Intermittent fasting sees you cutting calories very low for a few days a week.

Both of them have similar goals and whether or not MCT can break a fast is related to its potential effects on these.

Fasting for Health

One reason for fasting is that by taking the pressure off your digestive system you allow it to regroup and recover, which, it’s believed, may play a role in improving the health and diversity of the gut bacteria.

Cutting back food intake is also believed to stimulate the body’s process of clearing out damaged cells (known as autophagy). This happens because restricting calories and nutrients, cause mild stress to the cells – to counteract this the body aims to increase cellular efficiency which means cleaning them up so they effectively work better.

On top of this, intermittent fasting, where calories are restricted 2-3 days a week, has been shown to have a number of metabolic effects lowering things like sensitivity to the hormone insulin and reducing weight, particularly in regards to harmful visceral fat that collects around the organs.

You can find more benefits, and a discussion of the science of intermittent fasting here.

Fasting for Weight Loss

Some people also use intermittent fasting or, time-restricted eating as a way to lose weight.

While lots of reasons have been mooted for this – including the effects on insulin talked about above, basically, if you’re not nibbling snacks between the hours of say 8pm and noon the next day, or, you’re sticking to 800 calories a day 2-3 days a week, you naturally reduce the amount of calories you consume – and reducing calories is how we lose weight.

Another reason that fasting may lead to weight loss, is that you don’t provide your body calories for 10-12 hours, it uses up your body’s sugar stores and you turn to using your fat for energy (a state also known as ketosis) – and, if you then don’t overeat to replace that burned fat, its pretty clear why that triggers weight loss!

And this is where the confusion as to what breaks a fast comes in – because, different foods, drinks or supplements trigger different reactions in the body that might counteract one or other of these goals.

So, What Then Constitutes Breaking a Fast?

Debate rages about this.

Experts question whether breaking a fast means putting anything at all. that isn’t water, into your system.

Or is it just items that contain calories that might be classed as breaking a fast?

Or, is it foods that cause your insulin levels to increase and therefore kick you out of ketosis that break a fast?

To get a clear defintion, I asked Gabrielle Newman, nutritionist at The Fast 800 (the weight loss site headed up by scientist-turned-fasting-guru Michael Mosely). Here’s what she told me…

‘Simply put, fasting is when you stop eating and drinking anything containing calories for a period of time. Having said this, calorie restriction (consuming less calories) is also a form of fasting. 

Strictly speaking, therefore anything containing calories will break a fast – however, at The Fast 800, we have found that you will still reap the benefits of fasting even with something like a small splash of milk in your tea or coffee in the morning (around one tablespoon).

If you’re fasting to improve your insulin sensitivity though, then anything that causes an insulin response would class as breaking your fast whether it contains signifant calories or not.’

So, what does that mean about using MCT oil while fasting using this definition?

Does MCT Oil Break a Fast?

MCT oil is a supplemental source of fats called medium chain triglycerides. It’s usually derived from higher fat oils like coconut oil or palm kernel oil from which medium chain triglycerides are extracted.

It usually comes as a liquid that can be added to foods, or drinks like black coffee or tea, to make them more sustaining.

This is one reason why you might want to use MCT oil while fasting as it can help create a feeling of satiety that lets you prolong your fasting period for longer.

But the question is whether than trade off might actually have an impact on the benefits of fasting… so let’s compare it to Gabrielle’s criteria…

Does MCT Oil Contain Calories?

Like most fats, MCT oil contains calories – about 120-150 calories per tablespoon.

As this is more than a negligible amount of calories, then, consuming it should mean that the process of autophagy will stop or slow down and your fast is broken.

However, with MCT get a bit more complex…

MCT and Autophagy

Because of their chemical structure medium chain triglycerides are processed differently by the body than other types of fat.

They are not processed through the intestine, but instead go from the stomach straight to the liver where they are turned into ketones that the body uses a fuel in a fasted state.

And ketones are one of the things that trigger autophagy.

This may suggest that calories consumed in the form of MCT oil may not have the same affect on stopping autophagy than those from something sugary, or another fat like coconut oil – and if this is true, then it wouldn’t break your fast.

We just don’t have studies yet to prove it.

Does MCT Oil Take You Out of Ketosis?

Another definition of something that breaks your fast is something that raises insulin enough to take you out of ketosis and Gabrielle says that because the calories in MCT oil come solely from fat – ‘and fat doesn’t trigger any kind of raise in insulin, having an MCT coffee during your fasting window will keep you in ketosis and you’re likely to be able to fast a little longer if you wish.’

That means if your main goal of fasting is to keep your body in ketosis for as long as possible, black coffee (or black tea or green tea) with MCT oil won’t break your fast.

Does MCT Oil Break Intermittent Fasting?

Intermittent fasting sees you fasting by keeping calories under a certain amount on a fast day – and, if using MCT oil tips you over this, you’ve broken your fast.

‘Remember if you’re fasting for weight loss, you will need to consider the extra calories of including MCT oil in your day. It might be better therefore to just stick to black coffee on these days,’ says Gabrielle.

Does MCT Powder Break a Fast?

You can now also buy MCT oil in powdered form. This will likely have the same general effects as MCT oil – but, check the ingredients carefully.

Some binders used in MCT powders may contain carbohydrates and, if you’re very insulin sensitive even a small amount could be enough to change your insulin response.

This could be enough to kick you out of ketosis and then, the combination of calories and a change in your ketotic state would break your fast.

However, before you make your final decision whether to use MCT oil (or powder) while fasting, there’s something else to consider in determining whether it’s a good way to break a fast …

Is it Okay to Consume MCT Oil on an Empty Stomach?

Fasting or not, whenever you consume the first thing you eat or drink each day, you’re putting whatever you choose into a totally empty stomach, and, if it’s a drink like coffee, tea or MCT oil enhanced coffee or tea, you’re doing so without any food alongside it.

Now, sometimes that’s no problem at all, other times, it might lead to some issues to do with energy, blood sugar – or even the health of your teeth!

So, let’s have a look at what happens if you consume MCT oil first thing.

The good news is, taking the suggested dose of 1 tablespoon of MCT oil itself is unlikely to be related to any major concerns with energy or blood sugar if you consume it on an empty stomach.

Because it doesn’t cause insulin to be raised it won’t trigger energy fluctuations that you might get from consuming something sugary to break your fast.

However, MCT oil can upset the stomach if you don’t take it with food, particularly when you first start taking MCT oil or if you take too much at a time.

This can lead to problems like gas, bloating and diarrhea.

Why does MCT Oil Make You Poop?

Even if you’re not made uncomfortable by drinking MCT, you might find you need the bathroom quickly after using it.

That’s still a sign that the MCT oil is upsetting your digestive system a bit which then encourages it to move.

And if you’re having it in your morning coffee, there’s a double whammy – it’s been shown that within four minutes of drinking a cup of coffee, your bowel is stimulated to move.

The combo of MCT and coffee is a recipe for a quick trip to the bathroom.

And talking of coffee. Consuming coffee on an empty stomach can also be a problem.

As we talked about in our piece on why coffee might cause bloating, some people find the acidity of coffee too much on an empty stomach.

It can also slightly aggravate the stomach lining lead to bloating, gas and belching.

How to Use MCT Oil First Thing

If you do find that MCT coffee upsets your stomach if you do use it when fasting, try either reducing the amount of MCT oil you use and slowly building up your intake – or, try consuming it another way like in hot water.

If you’re just wanting to get any of the reported health benefits of MCT oil and not so worried about using it to help extend your fast, then using it when you’re also taking in some food might reduce the risk of digestive discomfort.

At this point, we need to mention that people with any kind of liver problem should not consume MCT oil at all – empty stomach or otherwise.

In Summary

Well, it seems that purely because of the amount of calories it contains, technically MCT oil does break a fast, but, depending the goal of that fast it may not have negative consequences.

However, it’s important to test whether consuming it on an empty stomach works for you or not.

And, if you’re trying to lose weight as part of your fasting regime, don’t forget to count the MCT calories as part of your daily intake.

So, there you have it, our discussion on whether MCT oil can break a fast. IF you have other questions about foods that might affect fasting, check out our What Does section which looks at the effects of other foods on the fasting state.


Who is The Wellness Nerd?

My name is Helen Foster and I’m a health journalist and wellness author. Publications I’ve written for include Women’s Health, Reader’s Digest, Body and Soul, Good Health at the Daily Mail and more. I have also written 16 books on health and nutrition.

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