Does Bulletproof Coffee Break a Fast? | Solid Grounds

Bulletproof coffee, a high-fat beverage combining coffee, MCT oil, and grass-fed butter, has sparked debate in the fasting community. While it technically breaks a fast due to its caloric content (210-230 calories per cup), its impact on fasting benefits is nuanced. The high fat content minimally affects insulin levels and may support ketosis, aligning with some fasting goals. However, it could potentially interrupt autophagy and gut rest. Proponents cite increased energy, improved focus, and prolonged satiety as benefits, while critics argue it may reduce fasting’s full advantages.

The decision to include bulletproof coffee in a fasting regimen depends on individual goals, metabolic responses, and health conditions. Alternatives include black coffee or modified recipes with reduced fat. Ultimately, the compatibility of bulletproof coffee with fasting varies based on personal objectives and definitions of fasting. Consultation with healthcare providers and self-monitoring can help determine its place in one’s fasting journey.

Does Bulletproof Coffee Break a Fast

Does Bulletproof Coffee Break a Fast? Exploring the Controversy and Considerations

In recent years, the intersection of bulletproof coffee and fasting has sparked considerable debate in health and wellness circles. As intermittent fasting gains popularity, many enthusiasts question whether consuming bulletproof coffee during fasting periods aligns with their goals or potentially undermines the benefits of fasting. This article delves into the complexities of this issue, examining the latest research and expert opinions to help you make an informed decision.

Understanding Bulletproof Coffee and Fasting

Bulletproof coffee, pioneered by Dave Asprey, is a high-fat beverage that combines coffee with MCT oil and grass-fed butter or ghee. Its proponents claim it provides sustained energy, improved mental clarity, and support for ketosis without significantly impacting blood sugar levels.

Fasting, on the other hand, involves abstaining from caloric intake for set periods. Popular methods include intermittent fasting (such as the 16:8 protocol) and extended fasts. People fast for various reasons, including weight loss, metabolic health improvement, and promoting cellular autophagy – the body’s process of cleaning out damaged cells.

The Composition and Caloric Content of Bulletproof Coffee

A typical cup of bulletproof coffee contains approximately 210-230 calories, primarily from fats. The main ingredients are:

  1. High-quality coffee: 0-1 calories
  2. MCT oil (1 tbsp): about 120 calories
  3. Grass-fed butter or ghee (1 tbsp): about 100 calories

This caloric content is the crux of the debate: does consuming these calories break a fast?

The Science Behind Bulletproof Coffee and Fasting

The effectiveness of bulletproof coffee in a fasting context lies in its fat composition. It contains a mix of long-chain fatty acids (LCFAs), medium-chain triglycerides (MCTs), and short-chain fatty acids (SCFAs). MCTs and SCFAs are metabolized differently from other fats, providing quicker energy and potentially supporting ketosis.

Grass-fed butter contributes butyrate, a beneficial SCFA, along with omega-3 fatty acids and fat-soluble vitamins. These components may offer health benefits, but the question remains: do they interfere with the fasting state?

Impact on Fasting States

Strictly speaking, consuming any calories breaks a fast. However, the impact of bulletproof coffee on fasting states is nuanced:

  1. Insulin Response: The high fat content of bulletproof coffee minimally affects insulin levels, potentially preserving some fasting benefits.
  2. Ketosis: MCTs can support or enhance ketosis, aligning with some fasting goals.
  3. Autophagy: There’s debate about whether the caloric intake from bulletproof coffee significantly interrupts autophagy. Some experts argue that the benefits of autophagy are primarily achieved after 16-24 hours of fasting, which may still be possible with bulletproof coffee consumption.
  4. Gut Rest: Consuming bulletproof coffee does stimulate the digestive system, potentially interrupting the gut rest that occurs during fasting.

Pros and Cons of Bulletproof Coffee During Fasting


  1. Increased energy and mental clarity
  2. Improved satiety, making fasting easier for some individuals
  3. Potential support for ketosis
  4. Provision of beneficial fats and fat-soluble vitamins


  1. Caloric intake, technically breaking the fast
  2. Potential interruption of autophagy and gut rest
  3. High saturated fat content, which may be concerning for some individuals
  4. Possible digestive discomfort for some people

Latest Research and Expert Opinions

Current research on bulletproof coffee and fasting is limited and often conflicting. Some studies suggest that consuming fats during fasting periods may not significantly impact the benefits of fasting, while others indicate that any caloric intake can interrupt fasting processes.

Dr. Jason Fung, a prominent fasting researcher, suggests that small amounts of fat during fasting may be acceptable for some people, especially if it helps them adhere to their fasting schedule. However, he emphasizes that strict water fasting is ideal for maximum benefits.

Other experts, like Dr. Rhonda Patrick, argue that any caloric intake, including bulletproof coffee, will break a fast and potentially reduce its benefits, particularly concerning autophagy and circadian rhythm regulation.

Individualizing Bulletproof Coffee Consumption

The impact of bulletproof coffee during fasting can vary widely among individuals due to metabolic differences. Factors to consider include:

  1. Personal fasting goals (weight loss, metabolic health, autophagy)
  2. Individual insulin sensitivity
  3. Existing health conditions (e.g., gallbladder issues, high cholesterol)
  4. Ability to maintain the fast without bulletproof coffee

Monitoring blood glucose levels and ketones can help individuals gauge their personal response and adjust consumption accordingly.

Alternatives and Modifications

For those wanting to maintain a stricter fast, alternatives include:

  1. Black coffee or tea (unsweetened)
  2. Modified bulletproof coffee with reduced fat content
  3. Consuming bulletproof coffee only during eating windows in intermittent fasting protocols

Ethical and Environmental Considerations

When considering bulletproof coffee, it’s important to note the ethical and environmental implications. Sourcing high-quality, sustainably produced coffee beans, MCT oil, and grass-fed butter can have significant environmental impacts. Consumers should be mindful of these factors when making their choices.

Conclusion: Does Bulletproof Coffee Break a Fast?

Technically, yes, bulletproof coffee does break a fast due to its caloric content. However, whether this matters depends on individual fasting goals and definitions. For those primarily seeking ketosis and appetite suppression, bulletproof coffee may be compatible with their fasting regimen. For those pursuing autophagy or strict calorie restriction, it may interfere with these goals.

Potential downsides include:

  1. Interruption of complete gut rest
  2. Possible reduction in autophagy benefits
  3. High calorie and saturated fat intake
  4. Potential digestive issues for some individuals

Ultimately, the decision to include bulletproof coffee in a fasting regimen should be based on personal health goals, individual responses, and consultation with healthcare providers. As with many aspects of nutrition and health, there’s no one-size-fits-all answer. Experimentation, self-monitoring, and staying informed about the latest research can help determine whether bulletproof coffee has a place in your fasting journey.

FAQs and Answers

Does bulletproof coffee technically break a fast?

Yes, bulletproof coffee technically breaks a fast. It contains approximately 210-230 calories per cup, primarily from fats. Any caloric intake is considered to break a fast in the strictest sense.

The main components that contribute calories are:

  1. MCT oil (about 120 calories per tablespoon)
  2. Grass-fed butter or ghee (about 100 calories per tablespoon)

The coffee itself contributes negligible calories (0-1 calorie).

While bulletproof coffee does break a fast from a caloric standpoint, its impact on fasting benefits may vary depending on individual goals and fasting protocols. Some argue that its high fat content minimally affects insulin levels and may preserve certain fasting benefits, particularly ketosis.

However, for those pursuing strict fasting for purposes such as autophagy or complete gut rest, bulletproof coffee would indeed interrupt the fasting state.

Ultimately, whether consuming bulletproof coffee aligns with your fasting goals depends on your specific objectives and how you define your fast. For some, the potential benefits may outweigh the technical breaking of the fast, while others may prefer to avoid any caloric intake during fasting periods.

Can I drink bulletproof coffee and still get the benefits of intermittent fasting?

Whether you can drink bulletproof coffee and still get the benefits of intermittent fasting depends on your specific fasting goals. Here’s a breakdown:

  1. Ketosis: Bulletproof coffee may help maintain or even enhance ketosis due to its high fat content, particularly MCTs. This aligns with some intermittent fasting goals.
  2. Weight loss: If your primary goal is weight loss, bulletproof coffee might be compatible. It can help with satiety and may support fat burning. However, be mindful of the added calories.
  3. Insulin sensitivity: The high fat content of bulletproof coffee has minimal impact on insulin levels, potentially preserving this benefit of fasting.
  4. Appetite suppression: Many find that bulletproof coffee helps control hunger, making it easier to adhere to fasting windows.
  5. Autophagy: This is where bulletproof coffee may interfere. The caloric intake, even if primarily fat, may reduce the autophagy benefits of a complete fast.
  6. Gut rest: Consuming bulletproof coffee does stimulate the digestive system, interrupting complete gut rest.
  7. Metabolic flexibility: Bulletproof coffee may still allow for some metabolic benefits, but perhaps not to the full extent of a water-only fast.

Ultimately, if your goals align more with ketosis, weight management, and easier fasting adherence, bulletproof coffee might be compatible with your intermittent fasting regimen. However, if you’re aiming for maximum autophagy or complete digestive rest, it may be best to stick to water, plain tea, or black coffee during fasting periods.

Remember, individual responses can vary. It’s worth experimenting and possibly monitoring markers like ketones or glucose levels to see how bulletproof coffee affects your personal fasting experience. Always consult with a healthcare provider before making significant changes to your diet or fasting routine.

How does bulletproof coffee affect autophagy during fasting?

The effect of bulletproof coffee on autophagy during fasting is a complex and somewhat controversial topic. Here’s a breakdown of the current understanding:

  1. Autophagy basics: Autophagy is a cellular cleaning process that’s believed to be enhanced during fasting periods. It’s typically triggered by nutrient deprivation and low insulin levels.
  2. Caloric intake: Bulletproof coffee contains calories (about 210-230 per cup), which could potentially interrupt the fasting state that promotes autophagy.
  3. Insulin response: The high fat content of bulletproof coffee has minimal impact on insulin levels. Since low insulin is important for autophagy, this aspect of bulletproof coffee may not significantly disrupt the process.
  4. mTOR pathway: Autophagy is inhibited by the activation of mTOR (mammalian target of rapamycin). While protein is the primary activator of mTOR, some studies suggest that certain fats might also have an effect, although to a lesser degree.
  5. Expert opinions: There’s disagreement among experts. Some, like Dr. Jason Fung, suggest that small amounts of fat during fasting may not significantly impact autophagy. Others, like Dr. Rhonda Patrick, argue that any caloric intake could potentially reduce autophagy benefits.
  6. Lack of direct research: There’s limited research directly studying the impact of bulletproof coffee on autophagy in humans during fasting.
  7. Individual variations: The effect may vary among individuals based on factors like metabolic health and fasting duration.

Current consensus: While not definitively proven, it’s generally thought that bulletproof coffee likely reduces the autophagy benefits compared to a complete fast, but may not eliminate them entirely.

For those prioritizing maximum autophagy, it’s often recommended to stick to water, plain tea, or black coffee during fasting periods. However, if bulletproof coffee helps you maintain a fasting practice and you’re seeing benefits, it may still be valuable as part of your overall health strategy.

As always, it’s best to consult with a healthcare provider and consider your personal health goals when deciding whether to include bulletproof coffee in your fasting regimen. More research is needed to fully understand the relationship between bulletproof coffee consumption and autophagy during fasting.

Will bulletproof coffee kick me out of ketosis during a fast?

Bulletproof coffee is unlikely to kick you out of ketosis during a fast. In fact, it may even support or enhance ketosis. Here’s why:

  1. Fat content: Bulletproof coffee is primarily composed of fats, which don’t significantly impact blood sugar or insulin levels. Ketosis is maintained when insulin levels are low.
  2. MCT oil: The medium-chain triglycerides (MCTs) in bulletproof coffee are rapidly absorbed and converted into ketones by the liver. This can actually increase ketone production and deepen ketosis.
  3. Minimal carbohydrates: Bulletproof coffee contains negligible carbohydrates, which are the primary macronutrient that can disrupt ketosis.
  4. Grass-fed butter: The butter in bulletproof coffee is high in fat and contains no carbs, supporting the ketogenic state.
  5. Potential boost to fat burning: Some studies suggest that the combination of caffeine and MCTs may enhance fat oxidation, supporting the body’s use of fat for fuel.
  6. Individual variations: While most people will maintain ketosis with bulletproof coffee, individual responses can vary. Factors like metabolic health and overall diet can influence how your body responds.
  7. Monitoring: If you’re concerned, you can monitor your ketone levels using blood, breath, or urine tests to see how bulletproof coffee affects your personal ketosis levels.

However, it’s important to note that while bulletproof coffee likely won’t disrupt ketosis, it does contain calories and will break a fast in the strictest sense. This may impact other fasting benefits like autophagy.

For those using fasting primarily as a way to maintain ketosis and for its potential metabolic benefits, bulletproof coffee can often be incorporated without concern. But if you’re aiming for the full range of fasting benefits, including maximum autophagy, you might choose to avoid bulletproof coffee during your fasting window.

As always, it’s best to listen to your body and possibly consult with a healthcare provider to determine the best approach for your individual health goals and needs.

Are there any downsides to consuming bulletproof coffee during a fast?

Yes, there are several potential downsides to consuming bulletproof coffee during a fast:

  1. Caloric intake: Bulletproof coffee contains about 210-230 calories per cup, which technically breaks the fast. This may reduce some of the benefits associated with complete calorie restriction.
  2. Interruption of autophagy: The caloric intake may interfere with the cellular cleaning process of autophagy, which is one of the key benefits of fasting.
  3. Digestive system stimulation: Consuming bulletproof coffee stimulates the digestive system, interrupting the gut rest that occurs during a complete fast.
  4. High saturated fat content: The high amount of saturated fat (from butter or ghee) may be a concern for individuals with certain health conditions or those at risk for cardiovascular disease.
  5. Potential digestive discomfort: Some people may experience digestive issues like nausea or diarrhea, especially when first introducing bulletproof coffee to their routine.
  6. Nutrient imbalance: Relying on bulletproof coffee during fasting periods may lead to an imbalance in nutrient intake, as it’s high in fat but lacks other essential nutrients.
  7. Caffeine dependence: Regular consumption may lead to caffeine dependence or affect sleep patterns if consumed later in the day.
  8. Dental health: The acidity of coffee, combined with the lack of food to buffer it, may potentially impact dental health over time.
  9. Complication of fasting routine: Including bulletproof coffee may make it more difficult to adhere to stricter fasts in the future.
  10. Individual metabolic responses: Some people might experience changes in blood lipid profiles or other metabolic markers, which should be monitored.
  11. Cost: High-quality ingredients for bulletproof coffee can be expensive compared to plain water or black coffee.
  12. Environmental considerations: The production of ingredients like grass-fed butter and MCT oil has environmental implications that some may want to consider.

It’s important to weigh these potential downsides against the benefits you’re seeking from both fasting and bulletproof coffee. The impact can vary greatly between individuals, so monitoring your own response and consulting with a healthcare provider is advisable when incorporating bulletproof coffee into your fasting regimen.