Does Butter in Coffee Break a Fast? (Solved & Explained!)

To put it plain and simply: yes, adding butter to your coffee will break your fast.

While there are certain health benefits to the famous “bulletproof” coffee (the drink that made the whole trend of adding healthy fats like grass-fed butter and MCT oil to coffee), keeping you in fast isn’t one of them.

Unless you’re actively in ketosis. Then it becomes more complicated. Let’s break it down.

What does breaking a fast actually mean?

Frankly speaking, consuming any calories breaks a fast. But what is it you’re fasting for, is what makes the question more complicated, since under a certain calorie threshold certain benefits can still be achieved, while others can not.

If you’re fasting, for example, to lose weight, or to regulate your blood sugar levels, then consuming a very limited amount of calories of foods with a low glycemic index should be fine.

If you’re fasting for longevity because you wish to trigger autophagy – the natural process of cleaning out damaged cells to regenerate newer, healthier cells – then consuming anything other than water is going to reduce the effects.

Why doesn’t black coffee considered to break a fast?

Technically, black coffee does break a fast. If you’re on any type of medicine you’re supposed to take fasted, a doctor will warn you that “taking it fasted” means taking it before you drink your morning cup of coffee – even if you drink it black.

A cup of black coffee contains only around 3 to 5 calories, with a minimal amount of protein, fats, and minerals. It not so much doesn’t break a fast but has such a little influence on the metabolic processes and overall daily calorie count, that it has become an acceptable concession.

Why add butter to the coffee in the first place?

The trend of adding butter to coffee was started by entrepreneur and self-proclaimed bio-hacker Dave Asprey. It’s supposed to emulate and increase the benefits of traditional Tibetan yak butter tea.

Yak butter tea has been used in Tibet as a healthy source of energy and calories for centuries now. It’s particularly beneficial in high altitudes, as Asprey himself experienced, since the energy boost it provides is steady and long-lasting, providing significant help while making long climbs.

Asprey thought to amplify the benefits of the drink by combining it with coffee. The fat from butter and MCT oil is supposed to slow down caffeine absorption, so instead of instant hit and subsequent crash, the energy boost you get from the coffee is supposed to last over a longer period of time.

Does it matter what kind of butter you’re adding to the coffee?

Asprey is adamant that simply adding a spoonful of any regular butter to your coffee isn’t going to achieve the effects bulletproof coffee is supposed to achieve.

The drink is supposed to be a source of healthy fats like organic grass-fed butter and/or ghee, as well as MCT oil.

That said, technically, most fats should be able to slow down caffeine absorption enough to prevent a quick crash. The taste, however, cannot be accounted for.

How did butter coffee become a trend in intermittent fasting?

Bulletproof coffee became something new intermittent fasters started turning to when the keto diet started becoming a trend.

Those who couldn’t stick to keto long-term and switched to intermittent fasting as means to cut down on daily calories and control insulin levels, kept bulletproof coffee in their diet due to its noticeable energy-boosting and appetite-suppressing qualities.

Why does butter in coffee not break a fast for a person in ketosis?

Again, technically it does. However, the overall effects it has on people in ketosis are vastly different than on regular Intermittent Fasters.

The one major difference is that if you’re in ketosis butter coffee will help with ketone production and subsequent fat burn.

If your primary goal with intermittent fasting is to lose weight and improve your metabolic function then adding healthy fats to your coffee – like organic grass-fed butter and MCT oil that the original bulletproof coffee recipe calls for – isn’t likely to impede your primary goals, as long as you remain in a calorie deficit.

Can you benefit from butter in your coffee if you’re NOT on keto?

Bulletproof coffee may not be compatible with standard intermittent fasting, but it can help you with weight loss if used smartly.

As an energy booster and an appetite suppressor, it can act as the first meal of the day and keep you from snacking/grazing until the time for your first meal comes.

If you’re only now transitioning to Intermittent Fasting, it can help you make that transition smoother.

But do keep in mind that a standard cup of bulletproof coffee has approximately 350 calories, so it should be treated as a MEAL, if you wish to remain in a calorie deficit to lose weight.

Are there any benefits to adding butter in coffee AFTER the fast has been broken?

If you’re the type to drink coffee during the day (say at lunch), then bulletproof coffee can act as a healthy snack that keeps you fuller for a longer amount of time as well as a source of a prolonged energy boost.

Adding butter in your coffee while doing 5:2 fast:

If you’re doing the type of fat called 5:2 then adding butter to your coffee may be well compatible with your fast.

That’s because 5:2 isn’t so much time-constrained, as calorie-constrained. 5:2 fast means you eat a regular healthy amount of calories for 5 days a week and severely limit your calories (at around 500) twice a week.

If you can stick to the calorie limitations while adding butter to your coffee – go ahead, you’re still considered to be fasting.

Can you add anything to your coffee without breaking a fast?

If you’re not fasting for longevity/autophagy, then the limited amount of calories you’re allowed on fast can be stretched a bit further than 3-5 calories a cup of black coffee provides, and add a splash of unsweetened milk or cream to your coffee.

The limit is thought to be around somewhere 30-40 calories and doesn’t allow for any refined carbs, sugars, or products with a high glycemic index (so no flavored creamers). This is sometimes referred to as “dirty fasting”.