What is a Dirty Fast?
Dirty fasting is a less restrictive version of intermittent fasting, allowing you to consume a minimal amount of calories during your fasting window. Unlike clean fasting, where only non-caloric beverages like water and black coffee are allowed, dirty fasting offers flexibility by permitting up to 100 calories. This allowance helps some people manage hunger and stick to their fasting schedule more easily, which can be particularly beneficial for beginners or those who struggle with strict deprivation.
Although it makes fasting more manageable, it is important to note that consuming calories, no matter how few, technically breaks a true fast from a metabolic standpoint. The goal of dirty fasting is to stay in a metabolic state where insulin levels remain low, and the body continues to burn stored fat for energy. Therefore, the types of food and drink allowed are strategically chosen to minimize the insulin response.
Acceptable foods and drinks on a dirty fast
The most important rule of dirty fasting is to keep your total caloric intake during the fasting window to a minimum, generally under 100 calories. Here is a list of commonly permitted items:
- Coffee with a splash of add-ins: While black coffee is a clean-fasting staple, a dirty fast permits a small amount of dairy, such as a splash of heavy cream or half-and-half (e.g., 1 tablespoon is about 50 calories). Some also include MCT oil or grass-fed butter, a popular practice in bulletproof coffee.
- Tea with additives: Similar to coffee, tea (green, black, or herbal) is permitted with small, low-calorie additions. A splash of cream or a zero-calorie sweetener, such as stevia, is acceptable, though some argue artificial sweeteners could trigger an insulin response.
- Bone broth: A savory, nutrient-dense beverage, bone broth is often cited as a dirty fast-friendly option. A single cup typically contains around 40 calories and can help curb hunger while providing valuable electrolytes and nutrients.
- Electrolyte supplements: Maintaining hydration is crucial while fasting. Sugar-free electrolyte supplements or adding a pinch of salt to water can replenish minerals lost during fasting without adding significant calories.
- Water (still, sparkling, or flavored): Water is always encouraged on any fast. Sparkling water is acceptable, but ensure it is unsweetened and free of artificial colors or sweeteners that could add unwanted calories or trigger a metabolic response. A squeeze of lemon or lime juice can be added for flavor.
- Low-calorie foods (in tiny portions): Some dirty fasting proponents allow for a very small, low-carb food item, such as a few nuts or a slice of avocado. However, this is a highly debated practice, as it risks triggering a more significant metabolic reaction and could lead to overconsumption.
Dirty fasting vs. clean fasting
Understanding the fundamental differences between these two approaches can help you decide which is best for your goals. The table below compares the key aspects of dirty and clean fasting.
| Feature | Dirty Fasting | Clean Fasting |
|---|---|---|
| Calorie Intake | Up to 100 calories during the fasting window. | Zero calories during the fasting window, with some exceptions for minimal-calorie drinks. |
| Flexibility | Higher flexibility, allowing for some small food or drink additives. | Stricter, with no calorie intake, which some find harder to adhere to. |
| Metabolic State | May not achieve a truly fasted state, as calorie intake can affect insulin levels. | Ensures a truly fasted state for maximum metabolic benefits like autophagy. |
| Hunger Management | Can help curb hunger and cravings by providing a small energy boost. | Requires stronger mental discipline to manage hunger pangs. |
| Ease of Entry | Often recommended for beginners as an easier entry point into intermittent fasting. | Can be more challenging for newcomers due to the all-or-nothing approach. |
Important considerations and tips
- Prioritize fats over carbs: If you are consuming a small number of calories, prioritize fats like MCT oil or healthy fats in bone broth over carbohydrates. Carbs will cause a more significant spike in blood sugar and insulin, counteracting the purpose of the fast.
- Stay hydrated: Dehydration is a common issue with any form of fasting, as you often get fluid from the foods you eat. Make an intentional effort to drink plenty of water, and consider incorporating sugar-free electrolytes to maintain mineral balance.
- Choose your additives wisely: Be mindful of the ingredients in your beverages. Artificial sweeteners are a point of contention, with some research suggesting they could provoke an insulin response. Whole, single-ingredient add-ins like a high-fat cream are generally a safer bet.
- Listen to your body: Dirty fasting is a tool for making fasting more accessible, not a rulebook to blindly follow. If consuming a certain item makes you feel unwell or triggers more intense cravings, it's best to avoid it. The goal is to find what works for your body and your lifestyle.
- Don't overdo it: The 100-calorie limit is not a license to graze. Use your calorie allowance strategically to combat extreme hunger or fatigue, not to fill your day with extra snacks.
Conclusion
For those who struggle with the strict calorie restriction of traditional intermittent fasting, dirty fasting offers a more flexible and approachable alternative. By allowing for a small number of calories, primarily from low-carb sources like bone broth, coffee with cream, or specific supplements, it can help manage hunger and make the fasting period more sustainable. While it may not provide the same extent of metabolic benefits as a true clean fast, dirty fasting can still be an effective tool for weight management and encouraging more mindful eating habits. It is important to remember that this is a theoretical concept with limited scientific research, and consulting a healthcare professional before starting any new dietary protocol is always recommended. Ultimately, success with dirty fasting depends on strategic choices and consistent practice.
You can read more about the differences between clean and dirty fasting here.
