If you practice intermittent fasting, you might wonder what drinks are safe during your fast. Black coffee and plain tea are usually fine, but what about newer options like mushroom coffee?
This guide will explain what mushroom coffee is, its nutritional profile, and how it fits into an intermittent fasting routine. We’ll look at the different types of fasts and how various mushroom coffee ingredients might affect them, so you can make an informed decision that aligns with your health goals.
What is Mushroom Coffee?
Mushroom coffee combines regular ground coffee beans with powdered medicinal mushrooms. Instead of common mushrooms, it uses adaptogenic varieties like Lion’s Mane, Chaga, Reishi, and Cordyceps, which are known for their health benefits. (Mushroom coffee benefits: What science says about this trending brew, 2025)
To make mushroom coffee, the mushrooms are dried, their beneficial compounds are extracted, and the resulting powder is mixed with coffee grounds. The drink tastes much like regular coffee, with a subtle earthy flavor and possible wellness benefits like better focus and immune support.
Most commercial mushroom coffees contain only a small amount of mushroom extract per serving, keeping the calorie count extremely low. A typical serving usually has fewer than 5 calories, with minimal carbohydrates, fat, or protein. (Calories in Four Sigmatic Mushroom Coffee and Nutrition Facts, 2024)
Does Mushroom Coffee Break a Fast?
The answer depends on your fasting goals and the ingredients in your coffee.
To answer fully, it’s important to know what it means to break a fast. Fasting is not just about skipping meals; it triggers processes like cellular repair and shifts your body from using glucose to burning stored fat. Eating calories can interrupt these changes. Mushroom coffee fits into different fasting scenarios:
For Strict Water Fasts
If you are on a strict water-only fast, then any beverage other than water—including mushroom coffee—is off-limits. The goal of this type of fast is zero caloric intake to maximize the body’s fasting-induced benefits.
For General Intermittent Fasting (Weight Loss & Metabolic Health)
Most people practice intermittent fasting for weight loss or metabolic health. For these individuals, the main goal is to keep calorie intake minimal to avoid a significant insulin response. A common rule of thumb is that consuming anything under 50 calories will not break a fast. (Will 10 calories break a fast?, n.d.)
- A regular cup of black mushroom coffee has fewer than 5 calories. This small amount is unlikely to cause an insulin spike or affect fat burning, so plain mushroom coffee is usually safe for intermittent fasting. (Can You Drink Mushroom Coffee While Fasting?, n.d.)
For Autophagy-Focused Fasting
Autophagy is the body’s process of cleaning out damaged cells and making new, healthy ones. Studies show that eating any protein or calories can slow this process. Even the few calories in mushroom coffee might reduce autophagy. (Does Mushroom Coffee Break a Fast?, n.d.)To minimize autophagy, it’s safest to stick to water, plain black coffee, or unsweetened tea. However, the impact of a 5-calorie drink is still debated and may be minimal. For a “dirty” fast, where you allow a small caloric intake, mushroom coffee could be an acceptable choice.
Watch Out for These Additives
Plain mushroom coffee is usually fine for fasting, but adding other ingredients can change that. Here are some common additives that will break your fast:
- Sugar and Sweeteners: Any form of sugar, honey, or syrup will add calories and spike your insulin, immediately breaking your fast.
- Milk and Cream: Dairy and most plant-based milks, such as oat or soy, have carbs, protein, and fat that can break your fast. A small splash of unsweetened almond milk might be okay for a less strict fast, but it’s usually best to skip it.
- MCT Oil or Butter: These are sometimes added to make ‘bulletproof’ coffee, but they have a lot of calories. They may not raise insulin like sugar does, but they can stop autophagy and prevent your body from burning stored fat. (Sperlazza & Courtney, 2025)
- Pre-Mixed Blends: Some mushroom coffee products are sold as lattes or have added coconut milk powder, sweeteners, or protein. Always read the nutrition label. If a serving has more than a few calories, it will break your fast. (Mushroom Coffee Latte, n.d.)
Making Your Decision
Deciding whether to include mushroom coffee in your fasting window comes down to your personal goals.
- If your goal is weight loss or metabolic flexibility, A plain, black mushroom coffee is unlikely to hinder your progress.
- If your goal is gut rest, the ingredients should be fine, as they are easy to digest.
- If your goal is to maximize autophagy, it’s best to stick with zero-calorie beverages like water or plain tea.
In the end, pay attention to how your body feels. If mushroom coffee makes you hungry or upsets your stomach while fasting, consider having it during your eating window instead.
Make Fasting Work For You
Mushroom coffee can be a good choice for people who fast, especially if you want to lose weight or improve your metabolism. Because it is low in calories, it won’t break your fast if you drink it plain. However, if your fasting goals are stricter, such as maximising autophagy, you may want to stick to water. Always check the ingredients of your mushroom coffee and avoid adding sugar, milk, or fat. By understanding how different components affect your body, you can successfully incorporate this unique beverage into your wellness routine.
