Butter Coffee Protein Shake (Bulletproof Style)

Why This Works for Intermittent Fasting

This fat-fuelled shake bridges the morning hours of a 16:8 or 18:6 window when hunger is at its peak. Grass-fed butter and MCT oil provide clean, ketone-producing fats that keep energy stable and suppress hunger without triggering a significant insulin response. Collagen protein adds a smooth, thick texture and supplies amino acids to support lean muscle during the fast. The result is sustained mental clarity and physical energy through the later hours of your fasting window — without the crash of a carbohydrate-based breakfast.

Ingredients

• 240ml (1 cup) strong brewed black coffee, hot or chilled (2 shots espresso also works)
• 1 tbsp grass-fed unsalted butter
• 1 tbsp MCT oil (or extra-virgin coconut oil as an alternative)
• 1 scoop unflavoured or vanilla collagen peptides or whey protein (approx. 20–25g protein)
• Pinch of sea salt
• ¼ tsp ground cinnamon (optional)
• 2–3 drops liquid stevia or monk fruit sweetener (optional — omit for strict clean fast)
• A few ice cubes if serving cold

Instructions

1. Brew your coffee. A strong espresso base or 240ml of freshly brewed black coffee works best. For a cold version, use chilled cold brew concentrate diluted 1:1 with water.
2. Add all ingredients to a blender. Pour the coffee into the blender jug first, then add the butter, MCT oil, protein powder, sea salt, cinnamon, and sweetener if using.
3. Blend on high for 20–30 seconds. The butter and MCT oil will emulsify into a smooth, creamy, latte-like consistency with a natural froth. Do not stir with a fork — blending is essential for the emulsion.
4. Taste and adjust. More richness: add another half tablespoon of butter. More sweetness: one extra drop of stevia.
5. Serve immediately. Pour over ice for a cold version, or drink hot from the blender jug. The emulsion will separate if left to stand, so drink within a few minutes.

Nutrition Per Serving

Nutrition is approximate and varies depending on protein powder brand and exact quantities used.

Fasting Compatibility

16:8 / 18:6 fasting (hunger management): This shake is best used as a hunger-management tool during extended fasting windows. Technically, the protein and fat content mean this is not a zero-calorie clean fast — it will provide energy and some amino acids. However, many practitioners use it to extend ketosis and prevent the physical hunger that leads to breaking the fast prematurely with a full meal. The fat and protein content keeps insulin low relative to a carbohydrate-based food.

Autophagy-focused fasting: If you are fasting specifically for autophagy benefits, stick to black coffee and water during the fasting window — even small amounts of protein activate mTOR and can partially interrupt autophagy. Save this shake for when you're ready to break the fast.

OMAD (one meal a day): Not suited for use during the fasting window. Save it for your eating window as a first drink before or with your meal.

Ketogenic diet: Fully keto-compatible. MCT oil promotes rapid ketone production, supporting both energy and mental clarity. This pairs well with a low-carbohydrate eating window following the fast.

Carnivore diet: Compatible when made with collagen or whey protein, butter, and MCT oil only. Skip the cinnamon and sweetener for strict carnivore use.

For a full breakdown of which fasting protocol best suits your goals, see which intermittent fasting protocol is best for beginners?.

For the complete guide to intermittent fasting, get Intermittent Fasting in Practice on Amazon. Buy the book and claim 3 months free on our fasting app at https://www.fastinginpractice.com/redeem.

Nutritional information is approximate. Consult a healthcare professional for personalised dietary advice.