Does Bulletproof Coffee Break a Fast? Intermittent Fasting and Bulletproof Coffee


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If you’re into intermittent fasting, like I am, you’ve probably heard of bulletproof coffee. If not, then you may not have any idea what it is – but I will explain it below.

The question here is, does bulletproof coffee break a fast? The answer is not straightforward, but I will break it down for you.

In this article, we’ll explore the science behind bulletproof coffee and fasting, and help you decide whether or not to incorporate this popular drink into your fasting routine.

Does Bulletproof Coffee Break a Fast

Does Bulletproof Coffee Break a Fast?

Intermittent fasting has gained significant popularity due to its potential health benefits and the flexibility it offers. One particular aspect that often sparks debate is whether consuming bulletproof coffee, or butter coffee, breaks a fast.

So, does bullet coffee break a fast or is it compatible with intermittent fasting?

Bulletproof coffee, also known as butter coffee, is a concoction that typically combines coffee, grass-fed butter, and medium-chain triglyceride (MCT) oil. Many enthusiasts of intermittent fasting have been drawn to this unique blend due to its reported ability to increase energy levels and promote mental clarity during the fasting period.

However, when it comes to determining whether bulletproof coffee breaks a fast, the answers can vary. Some argue that since bullet coffee contains calories from the added butter and MCT oil, it technically breaks the fast and disrupts the body’s metabolic state. These individuals believe that any caloric intake, no matter its source, can halt the fasting process.

Conversely, some proponents of intermittent fasting believe that bulletproof coffee can be included in the fasting window without disrupting its benefits. They argue that the few calories provided by the butter and MCT oil do not significantly impact insulin levels or hinder the autophagy process.

To clarify, autophagy is the natural cellular recycling and regeneration process that occurs during fasting, helping to remove damaged cells and potentially reduce the risk of various diseases. While there is limited scientific evidence specifically addressing the effects of bulletproof coffee on autophagy, some researchers suggest that the small amount of calories from the added fats may not interfere with this beneficial cellular process.

Bulletproof Coffee Intermittent Fasting

Bulletproof Coffee Intermittent Fasting

Calories and Insulin Response

Bulletproof coffee is a high-fat, low-carb drink that is supposed to keep you full and energized during your fasting period.

Bulletproof coffee does contain calories. One cup of Bulletproof coffee contains about 300 calories, which is a significant amount of energy.

Effect on Autophagy

Autophagy is a natural process that occurs in your body when you fast. It is the process of recycling damaged cells and removing toxins from your body. Some people worry that drinking Bulletproof coffee during a fast may interfere with autophagy because it contains calories and protein.

However, there is no scientific evidence to suggest that drinking Bulletproof coffee during a fast interferes with autophagy. In fact, some studies have shown that consuming small amounts of protein during a fast may actually enhance autophagy.

Impact on Ketosis

Ketosis is a metabolic state in which your body burns fat for fuel instead of carbohydrates. Many people who practice intermittent fasting do so to achieve a state of ketosis and promote weight loss. Bulletproof coffee is often touted as a way to enhance ketosis because it contains MCT oil, which is a type of fat that is quickly converted into ketones.

While Bulletproof coffee may help you achieve a state of ketosis, it is important to remember that it is not a magic bullet. Consuming too many calories, even if they come from fat, can still prevent you from achieving ketosis. Additionally, consuming too much fat can lead to digestive issues and other health problems.

Overall, whether or not Bulletproof coffee breaks a fast depends on your definition of fasting. While it does contain calories, it does not contain any carbohydrates or protein that would trigger an insulin response. Additionally, there is no evidence to suggest that it interferes with autophagy.

However, it is important to remember that consuming too much Bulletproof coffee can still prevent you from achieving your fasting goals.

Does MCT Oil Break a Fast?

MCT oil has become a popular supplement for those following an intermittent fasting (IF) diet. One common question among IF enthusiasts is whether or not MCT oil breaks a fast.

The short answer is no, MCT oil does not break a fast. However, it’s important to note that any substance that is metabolized by the body will technically break a fast. But in practice, taking a small dosage of MCT oil will not significantly affect the body’s fasting state.

Studies suggest that MCT oil can actually enhance the benefits of fasting. MCTs (medium-chain triglycerides) are a type of fat that are quickly metabolized by the liver and used for energy. Adding MCT oil to your diet while fasting can help reduce hunger and fatigue, allowing you to extend your fast.

Additionally, MCTs have been shown to improve insulin sensitivity and reduce acne breakouts. However, it’s important to consult with a healthcare professional before adding any new supplements to your diet, especially if you have underlying health conditions.

How to Make Bulletproof Coffee

How to Make Bulletproof Coffee

If you’re interested in trying out bulletproof coffee fasting, it’s easy to make. Here’s how:

  1. Brew 1 cup (8-12 ounces) of coffee.
  2. Add 1-2 tablespoons of MCT oil to the coffee.
  3. Add 1-2 tablespoons of butter to the coffee (grass-fed if you can get it).
  4. Blend the coffee, MCT oil, and butter together in a blender for 20-30 seconds until it looks like a creamy latte. (This is the generally recommended way but I actually just stir the butter into my coffee)

It’s important to note that the quality of the ingredients matters. Bulletproof coffee beans, Brain Octane C8 MCT oil, and grass-fed butter or ghee are recommended for the best results. You can also experiment with the ratios to find the perfect taste for you.

Some people also like to add a pinch of cinnamon or vanilla extract for added flavor. If you don’t have a blender, you can use a milk frother or a hand mixer to mix the ingredients together.

Remember, bulletproof coffee is not a magic solution for weight loss or health. It’s simply a way to add healthy fats to your diet and potentially improve cognitive function. As with any dietary change, it’s important to listen to your body and make adjustments as necessary.

Bulletproof Coffee FAQs

If you’re interested in trying bulletproof coffee while fasting, you may have some questions. Here are some of the most frequently asked questions about bulletproof coffee and fasting:

Will Bulletproof coffee break your fast?

Technically, yes. Bulletproof coffee contains calories from the butter and MCT oil, which can raise insulin levels and break a fast in some people. However, it will not raise blood sugar levels and prompt an insulin response in the majority of people.

Can you drink bulletproof coffee during intermittent fasting?

Yes, you can drink bulletproof coffee during intermittent fasting. However, it’s important to track your calorie intake and adjust accordingly. Drinking bulletproof coffee can help you feel full and focused during the fasting period, but it’s important to make sure you’re not consuming too many calories.

Is bulletproof coffee good for weight loss?

Bulletproof coffee can be a helpful tool for weight loss, in combination with other things but it’s not a magic solution. Drinking bulletproof coffee can help you feel full and focused, which can make it easier to stick to a calorie-controlled diet.

Can bulletproof coffee help with ketosis?

Drinking bulletproof coffee can help your body produce more ketones, which can be helpful if you’re following a ketogenic diet. The MCT oil in bulletproof coffee is quickly converted to ketones by the liver, which can help you stay in ketosis.

Is bulletproof coffee safe?

For most people, bulletproof coffee is safe to consume. However, it’s important to remember that bulletproof coffee is high in calories and can raise insulin levels. If you have a medical condition that affects your blood sugar or insulin levels, it’s best to talk to your doctor before adding bulletproof coffee to your diet.

Does coffee break a fast?

Black coffee does not break a fast as it has less than five calories and no carbs or protein. However, other types of coffee, particularly those that contain cream, milk or sugar, can break a fast as they contain calories.

Find out about all the different types of coffee drinks in our complete guide.


The question of whether bullet coffee breaks a fast or if butter coffee breaks a fast is a matter of interpretation within the intermittent fasting community.

While some believe any caloric intake disrupts the fasting state, others argue that the small amount of calories from the added fats does not significantly impact the benefits of fasting. It is crucial to strike a balance that aligns with your desired outcomes and consult with a healthcare professional or nutritionist if you are uncertain about incorporating bulletproof coffee into your fasting routine.

Ultimately, the decision of whether to include bulletproof coffee in your fasting routine depends on your individual goals and preferences. If your primary aim is weight loss or specific health benefits associated with fasting, it may be best to consume only water or black coffee during the fasting period. However, if the mental and energy-boosting effects of bulletproof coffee enhance your fasting experience without sabotaging your goals, it can be a personal choice to incorporate it.

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