What Can I Have During A Fast Foods Drinks?

If you are intermittent fasting, the short answer is that plain water, black coffee, and unsweetened tea are almost always fine to have during your fast. These drinks contain zero calories and will not break your fast in any meaningful way. Other options like diet soda, bone broth, or apple cider vinegar are more debated, and the answer depends on why you are fasting in the first place.

What Drinks Are Safe to Have During a Fast Without Breaking It?

The safest drinks during a fast are those with no calories, no sugar, and no artificial sweeteners that trigger an insulin response. Water is the gold standard. You can have tap water, sparkling water, or mineral water without issue.

Black coffee is also widely accepted. Research published in the Journal of Clinical Endocrinology & Metabolism found that caffeine can slightly increase fat oxidation, which may support the goals of fasting. Just avoid adding cream, milk, sugar, or any flavored syrups. A splash of unsweetened almond milk is debated — some purists say it breaks the fast, while others consider it negligible.

Unsweetened tea, whether green, black, or herbal, is also fine. Most herbal teas like peppermint or chamomile have virtually no calories. The exception is any tea with added fruit pieces or flavorings that may contain hidden sugars.

Can You Drink Diet Soda or Zero-Calorie Drinks While Fasting?

This is where the evidence gets murkier. Diet sodas contain artificial sweeteners like aspartame, sucralose, or stevia. These have zero calories, so technically they do not provide energy. But some studies suggest they may still trigger an insulin response in certain people.

A 2018 study in Cell Metabolism found that artificial sweeteners can alter the gut microbiome and glucose metabolism in some individuals. For someone fasting for weight loss, this might not matter much. For someone fasting for metabolic health or insulin sensitivity, it could be counterproductive.

If your goal is autophagy — the cellular cleanup process that happens during longer fasts — diet soda is likely not helpful. The body may still respond to the sweet taste as if food is coming, which could reduce the benefits of the fast. The safest approach is to stick with water, coffee, and tea.

What About Bone Broth, Apple Cider Vinegar, and Lemon Water?

Bone broth contains protein, fat, and calories. A typical cup has around 30-50 calories. For strict fasting, that breaks the fast. Some people doing “dirty fasting” allow bone broth because it provides electrolytes and may help with hunger. But if your goal is autophagy or maximum insulin sensitivity, bone broth is not recommended.

Apple cider vinegar is widely claimed to help with blood sugar control and weight loss. Some evidence supports this. A 2017 study in the Journal of Diabetes Research found that vinegar improved insulin sensitivity after a high-carb meal. But during a fast, you are not eating a meal. The effect on an empty stomach is unclear. Most experts say a tablespoon diluted in water is fine and unlikely to break a fast, though it may cause stomach irritation in some people.

Lemon water is another gray area. A squeeze of lemon in water contains minimal calories — about 1-2 calories per slice. That is not enough to break a fast for most people. But if you are fasting for autophagy or strict ketosis, even those few calories could matter. The consensus among fasting researchers is that lemon water is acceptable for general health fasting but not for strict therapeutic fasting.

What Does Research Say About Drinks and Intermittent Fasting?

The research on fasting has grown significantly in the last decade. Most studies focus on time-restricted eating, where people fast for 16-18 hours daily. In these studies, participants are typically allowed water and black coffee or tea. No study has found that these drinks interfere with weight loss or metabolic benefits.

A 2019 review in the New England Journal of Medicine summarized the evidence on intermittent fasting and noted that water and non-caloric beverages are standard in fasting protocols. The review also pointed out that even small amounts of calories — under 50 calories — may not disrupt the fasting state for most people.

That said, the definition of “fasting” varies. For religious fasting, any food or drink is prohibited. For health fasting, the rules are more flexible. The key is to be honest with yourself about why you are fasting and choose drinks that align with that goal.

What Can I Have During a Fast: Drinks That Support Hydration and Electrolytes

One overlooked aspect of fasting is electrolyte balance. When you stop eating, your body loses sodium, potassium, and magnesium through urine. This can cause headaches, fatigue, and dizziness.

Plain water does not replace electrolytes. If you are fasting for more than 24 hours, you may need to add electrolytes to your water. Options include:

• Unflavored electrolyte powders with no calories or sugar
• A pinch of sea salt in your water for sodium
• Mineral water that naturally contains magnesium and calcium
• Potassium citrate powder in small amounts

Do not use sports drinks like Gatorade or Powerade. They are loaded with sugar and calories. Even the “zero sugar” versions contain artificial sweeteners that may not be ideal. Stick with plain additives that have no calories and no flavor.

Comparison Table: Common Fasting Drinks and Their Effects

Common Misconceptions About Drinks During a Fast

One widespread myth is that anything with flavor will break a fast. That is not true. Flavor comes from compounds that do not contain calories. Black coffee and tea have strong flavors but zero meaningful calories. The taste alone does not trigger a metabolic response.

Another myth is that you cannot drink anything during a dry fast. That is true for dry fasting, but dry fasting is not recommended for most people. The vast majority of fasting protocols allow water. Dehydration is a real risk when fasting, especially in hot weather or during exercise.

Some people believe that coconut water is a good option because it is natural. Coconut water contains about 45 calories per cup and significant sugar. It will break a fast. It is a healthy drink in general, but not during a fast.

Finally, there is the idea that you can have any zero-calorie drink and still get the full benefits of fasting. As discussed, artificial sweeteners may affect insulin and gut health. If you are fasting for metabolic reasons, it is safer to avoid them.