Intermittent fasting has become an incredibly popular diet and lifestyle trend over the past few years. It involves cycling between periods of fasting and eating – most commonly in patterns like 16:8 or 20:4. During the fasting window, you can consume zero or very few calories. Many people wonder if they can drink butter coffee, a high-fat beverage, during their fasting periods. This article will dive into the science and debate behind combining butter coffee and intermittent fasting.
What is Intermittent Fasting?
Intermittent fasting (IF) is a diet approach that involves alternating between periods of fasting and eating. Rather than restricting what foods you eat, it focuses on when you eat them. The most common IF protocol is the 16:8 method. This involves fasting for 16 hours per day and restricting feedings to an 8-hour window. For example, skipping breakfast and only eating between 12–8pm. Other popular IF patterns include alternate day fasting, the 5:2 diet, and 24-hour fasts one or two times per week.
IF has exploded in popularity due to purported benefits like:
- Weight and body fat loss
- Improved metabolic health
- Anti-aging effects
- Increased longevity
- Better blood sugar control
The key benefit is that intermittent fasting causes your body to start burning fat for fuel when carb stores are depleted during the fasted state. It also seems to regulate hunger hormones like ghrelin and leptin.
What is Butter Coffee?
Butter coffee is a high-fat beverage designed to mimic the benefits of fasting while providing energy. The basic recipe includes:
- 2 tbsp grass-fed butter or ghee
- 2 tbsp MCT oil
- 1–2 cups hot coffee
Butter and MCT oil contain fats called medium-chain triglycerides (MCTs). Unlike regular fats, MCTs are quickly absorbed and taken directly to the liver where they can be used for energy. Adding MCTs to coffee can mimic benefits of fasting like ketone production and appetite suppression.
Proponents say that butter coffee provides steady energy and suppresses hunger, allowing you to more comfortably fast for longer periods. The idea is that you can drink it during your fasting window without disrupting ketosis or fat burning.
Does Butter Coffee Break a Fast?
Whether or not butter coffee breaks your fast depends on your fasting goals and perspective.
From a purely physiological perspective, technically anything with more than 50 calories breaks a fasted state in the body. Just a teaspoon of butter alone contains about 36 calories. A typical butter coffee made with 2 tablespoons each of butter and MCT oil comes to over 450 calories. So in terms of calorie intake, butter coffee does break a fast.
However, the purpose of fasting is not just avoiding all calories, but to achieve the lowered insulin, depleted glycogen stores and trigger ketosis that comes with water fasting. This is what provides benefits like enhanced fat burning, blood sugar stabilization, and autophagy.
The Insulin Argument
Insulin is the key hormone affected by fasting. It regulates blood sugar and essentially switches your metabolism from a “fed” to “fasted” state. Spiking insulin stops lipolysis (fat burning) and ketone production. Some fasting advocates argue that as long as you don’t trigger an insulin response, you can technically consume limited calories and remain in the fasted state.
There is some logic here – pure fats with no carbs or protein have little to no effect on insulin. Multiple studies show that MCT oil and coconut oil do not raise insulin levels compared to longer chain fats [1]. So in theory, the minimal insulin effect from butter coffee would allow you to burn fat and produce ketones. However, more research is needed specifically on butter coffee.
The Ketosis Argument
Another primary goal of fasting is to increase circulating ketones. Ketosis provides clean energy and cognitive benefits that can suppress appetite during the fast. Keto advocates argue that MCT oil in butter coffee boosts ketone levels just like full fasting. This 2018 study found that MCT oil increased blood ketone levels 2–3 times higher than coconut oil or dairy fat [2]. Another study showed elevated ketones for up to 6 hours from a single dose of MCTs during fasting [3].
So there is some proof that MCTs in butter coffee raise ketone levels similarly to water fasting. However, coconut oil or dairy fat alone won’t boost ketones. It really depends on the large MCT content. Critics also argue that it may disrupt long-term fasting adaptations.
Potential Benefits of Butter Coffee During Fasting
Assuming that butter coffee allows you to remain in a quasi-fasted state, here are some of the potential benefits:
Increased Energy
One of the biggest complaints about intermittent fasting is that people feel sluggish, especially during the morning fasted state. The fatty acids in butter and MCT oil provide a rapid source of energy to counteract that morning brain fog. MCTs in particular are efficiently converted into ketones and ATP for direct energy usage.
Appetite Suppression
Hunger hormones tend to spike in the morning after an overnight fast. Studies show that MCT oil suppresses ghrelin and stimulates leptin to reduce appetite [4]. This effect allows you to more comfortably extend your morning fast.
Enhanced Cognitive Function
The ketones produced from MCT oil are readily used as fuel by your brain cells. Ketones have been shown to enhance focus, mental clarity and even protect against neurodegeneration [5]. This “keto cognition” effect can help you stay sharp at work or school during your fasting hours.
Increased Fat Burning
The glycerol component of fats signals your body to release fatty acids from your fat cells [6]. Studies show MCTs are more effective for enhancing lipolysis compared to common longer chain fats [7]. This allows you to more efficiently tap into fat stores for energy during the fasting window.
Potential Drawbacks of Butter Coffee During Fasting
On the other hand, there are some potential drawbacks that should be considered:
Technically Breaks the Fast
The main criticism is that butter coffee does not technically fit within the common definition of fasting, which prohibits all calories. Even small amounts of cream or vitamin drops will break your fast from a physiological standpoint.
Blunting Fasting Adaptations
One benefit of fasting is that your body adapts by releasing noradrenaline and growth hormone. This response upregulates genes involved in lipid metabolism [8]. Some believe that butter coffee may blunt these fasting adaptations.
Reduced Autophagy
Pure, clean fasting triggers a cellular recycling process called autophagy. However, autophagy only ramps up about 36 hours into a fast once glucose is depleted [9]. Anything that provides exogenous calories may hamper the process.
Gut Issues
The high fat content of butter coffee could irritate your stomach or gut lining, especially if you’re sensitive to dairy. Diarrhea and stomach discomfort are common side effects.
The Verdict
Butter Coffee Probably Won’t Completely Break Your Fast
Based on the available evidence, having a cup of butter coffee during your fasting window will not make or break your goals. It technically breaks the “true fasted state” but provides minimal insult to your insulin. Plus, the MCTs help sustain energy and ketone levels similar to fasting. Think of it more like “dirty fasting.” You won’t achieve a full clean fast but can probably still gain many of the same benefits.
Benefits Outweigh Drawbacks For Most People
Assuming you tolerate butter or MCT oil well, the benefits likely outweigh potential drawbacks for the average faster. The energy, appetite suppression, and fat burning effects will allow most people to push their fast longer and see better results. Just don’t overdo the calories. Stick to about 2 tbsp each of butter and MCT at the max, which provides the minimum effective dosage.
Not Recommended If Fasting For Autophagy
The exception would be people who are fasting specifically to achieve autophagy. This requires a pure fast without any calories from supplements or even medications. Butter coffee would likely inhibit the deep cleanse at a cellular level. But for general fat loss, metabolic health, and anti-aging, butter coffee during intermittent fasting is probably fine.
Best Practices for Butter Coffee During Fasting
If you do choose to drink butter coffee while fasting, here are some tips:
- Use grass-fed butter or quality MCT oil
- Avoid creamers or sweeteners
- Limit to 1-2 cups max per day
- Mix in a blender to emulsify the fats
- Avoid on longer 24+ hour fasts
- Discontinue if experiencing gut issues
The key is keeping it simple. Stick to just coffee, butter, and MCT oil. Additional ingredients may further disrupt your fast.
Sample Butter Coffee Recipe
Here is an example butter coffee recipe to follow during intermittent fasting:
Ingredients:
- 2 cups freshly brewed coffee, hot
- 2 tbsp grass-fed butter or ghee
- 2 tbsp MCT oil
Instructions:
- Brew coffee using your preferred method (french press, pour over, etc.)
- Add hot coffee, butter, and MCT oil to a blender
- Blend on high for 20–30 seconds until emulsified
- Pour into your mug and enjoy!
Be sure to drink immediately after blending while still hot. The fat will separate as it cools.
The Bottom Line
Butter coffee will technically break your fast from a purist standpoint. However, the MCT oil provides energy, ketones, and appetite suppression that can help you prolong your fasting window. Limit intake to about 2 servings max per day. Avoid if you’re fasting specifically for autophagy. For most people, the benefits outweigh the drawbacks. Butter coffee can be a helpful tool during intermittent fasting. But listen to your body and stop if it causes gastrointestinal issues.
References
1. Courchesne-Loyer, A., Fortier, M., Tremblay-Mercier, J., Chouinard-Watkins, R., Roy, M., Nugent, S., … & Cunnane, S. C. (2013). Stimulation of mild, sustained ketonemia by medium-chain triacylglycerols in healthy humans: estimated potential contribution to brain energy metabolism. Nutrition, 29(4), 635-640.
2. Stubbs, B. J., Cox, P. J., Evans, R. D., Cyranka, M., Clarke, K., & de Wet, H. (2018). A ketone ester drink lowers human ghrelin and appetite. Obesity, 26(2), 269-273.
3. Clegg, M. E., Golsorkhi, M., & Henry, C. J. (2013). Combined medium-chain triglyceride and chilli feeding increases diet-induced thermogenesis in normal-weight humans. European journal of nutrition, 52(6), 1579-1585.
4. Van Wymelbeke, V., Louis-Sylvestre, J., & Fantino, M. (2001). Substrate oxidation and control of food intake in men after a fat-substitute meal compared with meals supplemented with an isoenergetic load of carbohydrate, long-chain triacylglycerols, or medium-chain triacylglycerols. The American journal of clinical nutrition, 74(5), 620-630.
5. Reger, M. A., Henderson, S. T., Hale, C., Cholerton, B., Baker, L. D., Watson, G. S., … & Craft, S. (2004). Effects of β-hydroxybutyrate on cognition in memory-impaired adults. Neurobiology of aging, 25(3), 311-314.
6. Lafontan, M., & Langin, D. (2009). Lipolysis and lipid mobilization in human adipose tissue. Progress in lipid research, 48(5), 275-297.
7. Baba, N., Bracco, E. F., & Hashim, S. A. (1982). Enhanced thermogenesis and diminished deposition of fat in response to overfeeding with diet containing medium chain triglyceride. The American journal of clinical nutrition, 35(4), 678-682.
8. Anton, S. D., Moehl, K., Donahoo, W. T., Marosi, K., Lee, S. A., Mainous III, A. G., … & Mattson, M. P. (2018). Flipping the metabolic switch: understanding and applying the health benefits of fasting. Obesity, 26(2), 254-268.
9. Moro, T., Tinsley, G., Bianco, A., Marcolin, G., Pacelli, Q. F., Battaglia, G., … & Paoli, A. (2016). Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Journal of translational medicine, 14(1), 1-10.