Foods That Break a Fast: What You Can (and Can’t) Eat While Fasting

Three hours into a 16-hour fast, hunger hits. Many people wonder: will a splash of cream in coffee ruin everything?

This guide shows exactly what breaks fast and what doesn’t. Readers will learn which foods stop fat burning, what can be safely consumed during fasting, and how to break a fast without digestive issues.

What Does “Breaking a Fast” Actually Mean?

Breaking a fast means eating or drinking something that shifts the body out of its fasted state. But what happens in the body matters more than the definition.

Research from Johns Hopkins shows that after 12-16 hours without food, insulin levels drop and the body starts burning fat for energy. This process is called metabolic switching. The body switches from burning sugar to burning fat, and scientists believe this metabolic shift provides health benefits.

Any amount of calories breaks fast. But the real question is whether those calories stop the benefits someone is fasting for. Weight loss goals have different rules than fasting for cellular cleanup (autophagy).

The 50-Calorie Rule (And Why It Matters)

Many experts use 50 calories as a practical threshold; staying under this amount likely won’t completely disrupt the fasting state for metabolic purposes. But there’s no hard science proving this exact number.

The type of calories matters more than the count. Fat calories have minimal impact on insulin levels compared to carbohydrates, which spike insulin quickly and pull the body out of fat-burning mode. Protein causes a moderate insulin response.

For autophagy benefits, the body’s cellular cleaning process, even small amounts of calories might interrupt the process. If cellular repair is the goal, sticking to zero calories is best.

Those unsure about how many hours to fast can use our fasting calculator to find their perfect schedule.

Drinks That DON’T Break a Fast

Water: Water is always safe. Staying hydrated during the fasting window is essential. This includes plain sparkling water.

Black Coffee: Black coffee has about 5 calories per cup, which is technically not zero, but most people drink it during fasting periods and do fine. Milk, creamer, or sugar should be avoided. Those additions will break fast.

Plain Tea: Brewed tea typically contains the same calories as black coffee or less. The same rules apply; no sweeteners or milk.

Apple Cider Vinegar: Apple cider vinegar is often allowed in small amounts during fasting. It should be mixed with water.

Drinks That WILL Break a Fast

Coffee with Additions: Adding milk, creamer, or sugar to coffee will break a fast. That Venti iced coffee with whipped cream ends a fast immediately.

Flavored Waters: Flavored waters usually contain some calories. Plain water is the better choice.

Juice and Smoothies: Both contain significant calories and sugar. They trigger an insulin response and stop fat burning.

Alcohol: Alcohol contains calories and disrupts metabolism. It should be saved for the eating window.

Diet Soda: This one’s debatable. Artificial sweeteners might trigger an insulin response in some people, though the science isn’t clear.

The Gray Area: Things That “Technically” Break a Fast

Some additions fall into a gray zone. They contain calories but might preserve some fasting benefits.

Bone Broth: Bone broth contains calories but some experts say it maintains ketosis. It won’t preserve autophagy, but it might help people stick to their fasting schedule.

MCT Oil or Coconut Oil in Coffee: Pure fat might maintain some fasting benefits. A “fat fast” can be effective to curb hunger while keeping insulin and cortisol levels lower. But it will reduce autophagy.

Supplements During Fasting: Safe options: Creatine is calorie-free and doesn’t trigger an insulin response. Prebiotics and probiotics don’t contain digestible carbs or calories.

Avoid gummy multivitamins. They contain sugar, protein, and fat. Protein powders trigger an insulin response. BCAAs trigger insulin that opposes autophagy. If people experience fasting headaches, adding salt to the diet can help prevent common symptoms.

Those seeking personalized fasting advice can chat with our AI assistant for answers to specific questions.

Best Foods to Break a Fast (When the Window Opens)

When the eating window opens, starting gently is the key. Choosing easily digestible whole foods packed with nutrients is recommended.

Bone Broth: Bone broth is rich in electrolytes like potassium, sodium, magnesium, and calcium. It’s extremely easy to digest. The proteins are already partially broken down, so the body doesn’t work as hard.

Eggs: Eggs provide complete protein and are easy on the stomach. Scrambled, boiled, or poached all work well.

Berries and Melons: These fruits are low in sugar and hydrating. They won’t spike blood sugar as much as tropical fruits.

Fish: Fish provides protein plus omega-3 fatty acids. Salmon, tuna, or white fish are excellent choices.

Cooked Vegetables: Cooked vegetables are gentler on digestion than raw ones. Steamed broccoli, roasted carrots, or sautéed spinach work well.

Avocados: Avocados provide healthy fats and are filling. They help stabilize blood sugar.

Fermented Foods: Foods like yogurt, kefir, or sauerkraut support gut health.

The winning combination: prioritizing protein, healthy fats, and low glycemic carbohydrates to stabilize blood sugar and support energy levels.

A practical approach: Eating a piece of cheese 15 minutes before having steel-cut oats with protein powder, nuts, and berries. Or trying one hard-boiled egg before eating salmon, steamed vegetables, avocado, and feta.

Foods to AVOID When Breaking a Fast

After fasting, overwhelming the gut should be avoided. It’s been taking a break.

High-Sugar Foods: Foods high in sugar spike insulin and can cause digestive issues. Cake, cookies, and candy should be skipped.

Heavy, Fatty Meals: Foods like cheeseburgers are too heavy and can cause discomfort. These should be saved for later in the eating window.

High-Fiber Foods (Initially): Breaking a fast with high-fiber foods like legumes might cause digestive discomfort and bloating. Lentils and chickpeas can wait.

Spicy Foods: Fasting may increase sensitivity to capsaicin, the compound in chili peppers. Starting mild is recommended.

Large Portions: Flooding the system with hard-to-digest nutrients should be avoided. Starting with a small portion and eating more if still hungry works best.

Eating the wrong foods can lead to dumping syndrome, causing nausea, cramping, and diarrhea.

For more guidance on breaking a fast properly, readers can check Healthline’s research-backed guide and GoodRx’s nutrition recommendations.

Important Safety Information

Intermittent fasting shouldn’t be attempted by those under 18, pregnant women, breastfeeding mothers, people with type 1 diabetes who take insulin, or those with a history of eating disorders.

Always checking with a doctor before starting intermittent fasting is essential. Some people need medical supervision.

Listening to the body is crucial. If someone feels ill during a fast, it should be broken immediately with a small, healthy snack.

For a complete breakdown of who should avoid fasting and detailed safety information, check our comprehensive guide.

The Bottom Line

Breaking a fast is simple once the rules are understood. During the fasting window, sticking to water, black coffee, and plain tea is recommended. Technically, any calories break a fast, but staying under 50 calories likely won’t completely disrupt most metabolic fasting benefits.

When ready to eat, starting with gentle foods works best. Bone broth, eggs, berries, fish, cooked vegetables, and avocados are excellent choices. Sugar, heavy meals, and large portions should be skipped at first.

The best foods to break a fast are those that make people feel good. Starting simple, listening to the body, and adjusting as needed produces the best results.

Those ready to start a fasting routine can use a fasting tracker to build a schedule that fits their lifestyle, and connect with an AI assistant for any questions along the way.