Does bulletproof coffee break a fast? –– Explained by SIMPLE

Written by Melissa Renae

Medically reviewed by Louise Bula, RD

Published on February 6, 2024 | Updated on May 3, 2024

Coffee, ah –– the good stuff! It’s one of the most commonly consumed beverages around the world. So it’s no wonder we often get questions about all things coffee, especially “Does coffee break a fast?”  

We love questions like that around here because they are all about finding the best ways to customize intermittent fasting to your goals and preferences. Another common question we get asked about coffee is, “Does bulletproof coffee break a fast?” We’ll answer that question here, but feel free to check out our other resources and tools to help answer other questions like “What to eat during intermittent fasting?” and “What can you drink while fasting?” 

One question we can quickly answer, besides “Will bulletproof coffee break my fast?” is that intermittent fasting is not recommended for everyone. If any of the following sound like you, we don’t recommend trying intermittent fasting. 

If you 

• are pregnant, breastfeeding, or trying to conceive
• have type 1 diabetes
• are on prescription medications 
• are under the age of 18 or 80 years or older 
• are extremely active
• have a body mass index (BMI) < 18.5
• have an eating disorder or a history of one (or are at risk of developing one)

Otherwise, bring all your “What breaks a fast?” questions to us, but be sure to start with our SIMPLE quiz for a more personalized approach.

What is bulletproof coffee? 

What is bulletproof coffee anyway? No, it won’t turn you into a superhero, and you don’t need magic coffee beans to make it. Its “bulletproof” status comes from adding MCT oil and grass-fed ghee (clarified butter). 

Nutritional value

Bulletproof coffee usually contains about 200 to 300 calories from saturated fats. It may contain some vitamin K2 and A from the grass-fed butter but otherwise offers no other nutrients. 

Will bulletproof coffee break a fast?

So, does bulletproof coffee interrupt your fasting window? By our standards, yes, it does. We consider anything over 10 calories as a break in fasting. At about 200 calories per cup, we recommend you consume bulletproof coffee during your eating window. 

Health benefits and possible drawbacks of drinking bulletproof coffee while intermittent fasting

Benefits

• Appetite control –– Although bulletproof coffee’s high calorie content will break your fast, it can help keep you feeling full longer.

• Blood sugar control –– Bulletproof coffee will not spike your blood sugar during intermittent fasting as it contains no carbohydrates. This can be helpful in supporting the link between intermittent fasting and insulin resistance.[1]  

• Weight loss ––  Because the calories in bulletproof coffee are from fat, it may support weight loss by helping your body remain in ketosis and use fat for fuel.[2]

Drawbacks

• May impact your heart health –– Bulletproof coffee contains a high amount of saturated fats. They have long been known to increase blood lipids and increase the risk of cardiovascular disease.[3] If you’re at high risk for heart disease, you may want to skip the bulletproof coffee and include more healthy fats [4] –– i.e., avocado, oily fish such as salmon, and unsalted nuts such as walnuts.

• May be a poor substitute –– High in calories but low in beneficial nutrition, it doesn’t compare with a balanced breakfast. Since intermittent fasting is broken by bulletproof coffee, starting your eating window with a nutrient-rich and balanced breakfast would be more beneficial. 

Tips on drinking bulletproof coffee during a fast

• Timing is everything –– If you’re going to include bulletproof coffee while fasting, have it during your eating window and consider pairing it with a light breakfast that has fiber and protein — think fat-free Greek yogurt with berries. Or you could save it for an afternoon pick-me-up, but you may want to switch to decaf. 

• Moderation is key –– Including bulletproof coffee in your everyday routine may not be the best idea. It contains about 1.5 times the recommended amount of daily saturated fat for a 2,000-calorie diet.[5] 

Check in –– Be sure to check with your doctor before adding anything new to your diet, including bulletproof coffee or starting intermittent fasting. Knowing where your blood lipids stand before starting with bulletproof coffee would be a good idea.

Written by Melissa Renae

Medically reviewed by Louise Bula, RD

Published on | Updated on May 3, 2024