When Fasting Can You Drink Coffee: It Depends on the Reason

Are you thinking about trying intermittent fasting? Do you have to fast for an upcoming doctor's appointment? When fasting, can you drink coffee? Learn more about this topic below! 

when fasting can you drink coffee - black coffee and utensils at the top of a table mat
Black coffee can impact your blood sugar levels

Whether you have weight loss goals, are trying to follow a new diet, or have an upcoming doctor's appointment, you may have to fast from time to time. If you are trying intermittent fasting, you may have questions about what you can and cannot drink.

For example, will a cup of coffee violate your fasted state? Is this going to kick you out of ketosis? How will this impact your blood pressure and blood sugar levels?

Before you reach for that cup of joe, understand how this might impact your intermittent fast. Whether you can drink one or two cups of coffee during your fasting period depends on why you are fasting. Take a look at some helpful information we have put together! 

Drinking Coffee Can Impact Your Blood Test Results

First, if you have a doctor's appointment coming up, understand that even black coffee can impact your blood sugar levels. Even though the carb content of black coffee is negligible, and it is close to calorie-free, coffee still has caffeine in it. Therefore, coffee consumption can impact your heart rate and blood pressure, throwing off your vital signs when you arrive at the doctor's office. 

Furthermore, coffee is also a diuretic. This means that it can dehydrate you. This can impact a wide variety of blood test results.

This includes your electrolyte levels, your cholesterol levels, and even your liver enzymes. There is a reason why doctors want you to have an empty stomach when you arrive at the office for a blood test. Whether you are drinking decaffeinated or regular coffee, your blood test results might be thrown off. 

Bulletproof Coffee: Helpful for Ketosis

If you are trying to follow the keto diet, there are certain types of coffee you should stay away from. For example, sweeteners will quickly cause your body to stop producing ketones. Your body enters a state of ketosis when it does not have any carbohydrates to consume.

Without carbohydrates, your body starts burning fat for energy instead. That is where ketosis comes from. 

If you supply your body with carbohydrates, it will stop producing ketones, hurting your weight loss goals. If you are looking for coffee you can drink on the keto diet, then Bulletproof Coffee might be for you. 

Bulletproof Coffee contains MCT oil, which drives up its fat content. On the keto diet, you will consume a lot of fat, encouraging your body to stay in ketosis. Even though Bulletproof Coffee can provide you with a lot of energy, it does contain calories (and a lot of them).

Therefore, this is a beverage that you should drink in moderation. 

Can You Drink Coffee on an Intermittent Fast?

clock, knife and fork on a wooden board
Intermittent fasting with coffee may reduce inflammation throughout the body

Drinking moderate amounts of zero-calorie or low-calorie beverages during an intermittent fast will not break your fast.

This includes black coffee. A single cup of black coffee only contains between two and three calories. Therefore, this should not ruin your fast. 

There are numerous benefits of intermittent fasting with coffee as well. For example, intermittent fasting with coffee may reduce inflammation throughout the body. If you are someone who suffers from aches and pains, intermittent fasting could help you reduce inflammation, making you feel more comfortable.

It is also possible that drinking coffee regularly while fasting could reduce your risk of developing heart disease. On the other hand, there are a few drawbacks as well. For example, one study showed that drinking multiple cups of coffee in a day could increase insulin levels.

This suggests that multiple cups of coffee could reduce your insulin sensitivity, impacting your metabolic health. If you are trying intermittent fasting for the first time, you should monitor how this impacts your body. 

Final Word on When Fasting Can You Drink Coffee

If you are fasting, you need to follow the guidelines carefully. In some cases, you may be able to drink coffee. In other cases, you might not be allowed to drink coffee.

It depends on why you are fasting.

For example, if you are giving intermittent fasting a try, you may be able to drink black coffee. Because black coffee has a low number of calories, this should not break your fast.

On the other hand, you should try not to add sweeteners to your coffee. This could break your fast. It will certainly break you are state of ketosis if you are trying the keto diet. 

Finally, if you have a doctor's appointment coming up, your doctor may have told you to fast. Your doctor needs you to fast to ensure the accuracy of your blood test results. Because coffee contains caffeine and soluble plant matter, it can throw off your vital signs and blood work.

Follow the instructions of your doctor if you have been told to fast. 

FAQs About When Fasting Can You Drink Coffee

Can I drink coffee on the keto diet? 

Black coffee is keto-friendly. On the keto diet, you need to limit your intake of carbohydrates. Black coffee does not contain a lot of carbohydrates.

You can drink this on the keto diet. On the other hand, you cannot add any sugar or sweeteners to your coffee. Otherwise, this will knock your body out of ketosis. 

Can I drink coffee while fasting intermittently?

If you are in a fasting window on the intermittent fasting diet, you can still drink black coffee. Black coffee only contains between 2 and 3 calories. Therefore, this should not break your fasting period.

Will drinking coffee impact my blood test results? 

There are certain blood tests that require you to fast before your blood is drawn. If your doctor has told you to fast, do not drink coffee. This can throw off the results of many common blood tests including cholesterol panel, blood sugar levels, and renal function panels.