Intermittent Fasting: What Breaks a Fast?

What Breaks an Intermittent Fast?

Man drinking a cup of coffee

If you’re new to intermittent fasting , you may have a lot of questions about what to do while fasting * . Does coffee break a fast? What about diet soda, or tea? Can I eat a banana? Or a handful of almonds? What if I’m really hungry? Read on to discover what really breaks a fast, and how to curb hunger while intermittent fasting for greater success.

What Breaks a Fast?

Strictly speaking: any amount of calories, no matter how small, disrupts the fasting process. If you’re following your intermittent fasting plan to the letter, that means no calories, whatsoever, for the entirety of your fasting window. In order to preserve the benefits of intermittent fasting —burning fat for fuel, controlled blood sugar levels, etc. 1 —it is not generally recommended to consume anything other than a few select beverages during the fasting window.

What Can You Drink While Fasting?

While eating is definitely off the table while in your fasting window, many people find success with a variety of beverages that can help preserve the benefits of fasting while simultaneously curbing hunger pangs. Here’s a rundown of a few of the most common:

  • Water.

    Staying hydrated is the most important component to a successful fast. Choose still or sparkling, but be sure to check the label on flavored water, which may have hidden carbs.

  • Coffee and tea.

    If you can’t imagine your mornings without a cup of coffee or tea, don’t fret! Black coffee and tea contain so few calories (3 calories and 2 calories, respectively; though tea varieties may vary) that you may find they don’t impact your fast at all. Or, you may find that the benefits outweigh the negligible calories. Just be careful to reach for low carb and calorie creamers and sweeteners, if at all.

  • Broth.

    While broth will technically break your fast, it contains high levels of necessary sodium and other minerals, which helps your body replenish electrolytes and stay hydrated while also fighting off hunger pangs. 2 Most broths also contain very few calories (1/2 cup bone broth contains ~15 calories.)

What Can You Eat While Fasting?

As previously stated, any amount of calories will, technically, break your fast. Even foods with extremely low calories, like celery, still contain fiber and other nutrients that could potentially trigger your body’s digestive process. It’s also possible that the effect of chewing may get your digestive system working, which will actually make you feel hungrier. Therefore, it is not generally recommended to eat during the fasting window.

However, everyone is different, and you should always find what works and feels best for you. What’s key to any weight loss plan—and essential to learning how to curb hunger during intermittent fasting—is consistency. If a small boost helps you see your fasting window through to the finish, and to start fasting again when scheduled, then go for it! And, as always, if you’re feeling faint or ill, you should listen to your body and eat or drink when needed.

Plus, even if your body is no longer in fasting mode, you can still benefit from some of its processes; fat-burning ketosis , for example, still occurs after feeding, so long as you remain under 50 grams of carbs per day. 3 Keeping your blood sugar levels stable is also possible after fasting; just stick with low carb foods to avoid spiking your blood sugar, and keep your body in fat-burning mode. Ultimately, what’s important about intermittent fasting is finding the right tools that help you stick to your routine, rather than preserving the technicality of the fast.

* Before starting IF, consult with your doctor or healthcare provider for guidance on whether IF is right for you.

Further Reading
PubMed Central, National Library of Medicine, 2022: A scoping review of intermittent fasting, chronobiology, and metabolism

Chronobiology plays a crucial role in modulating many physiologic systems in which there is nutritional synergism with meal timing. Given that intermittent fasting (IF) has grown as a flexible dietary method consisting of delayed or early eating windows, this scoping review addresses the effects of IF protocols on metabolism as they relate to clinical nutrition and the circadian system…

Evidence Based
PubMed Central, National Library of Medicine, 2005: Soup and satiety

Energy-yielding fluids generally have lower satiety value than solid foods. However, despite high water content, soups reportedly are satiating. The mechanisms contributing to this property have not been identified and were the focus of this study…

Evidence Based
PubMed Central, National Library of Medicine, 2021: Alternative Dietary Patterns for Americans: Low-Carbohydrate Diets

The decades-long dietary experiment embodied in the Dietary Guidelines for Americans (DGA) focused on limiting fat, especially saturated fat, and higher carbohydrate intake has coincided with rapidly escalating epidemics of obesity and type 2 diabetes (T2D) that are contributing to the progression of cardiovascular disease (CVD) and other diet-related chronic diseases…

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