WebMD BlogsPublic Health

'Can I Drink Coffee While Fasting?'

coffee
By Elizabeth Hanes, BSN, RNJuly 06, 2020

I heard the same question almost every time I gave pre-op instructions to a patient: Once I got to the part about “nothing to eat or drink after …”, nearly every one of them would look at me in anguish and ask, “Does that mean no coffee??”

I feel you.

As a connoisseur of caffeine, myself, I understand that fasting can be difficult enough without giving up coffee to do it. And the good news is: sometimes you don’t have to!

The answer to this question depends on the type of fasting you’re doing. Can you drink coffee while doing …

Pre-surgical fasting? No, you absolutely may not drink coffee (or water – or beverages of any kind) after the cut-off time you’re given. That’s because the medications used in general anesthesia make it easy for stomach contents to regurgitate into the esophagus, where they can be inhaled. Not good. So, you should never eat or drink anything for several hours prior to a surgery with general anesthesia.

Fasting before blood tests? Yes, in most cases, you may drink black coffee before a “fasting” blood test (or black tea if that’s your preference). These beverages generally will not affect the results of common fasting lab tests, like cholesterol (lipid panel), metabolic panel or blood glucose. To be safe, though, you should ask your doctor or call the lab in advance to see if you can enjoy your morning java fix before you get your blood drawn. And what happens if you cheat and add cream or sugar to your coffee before a fasting lab test? Well, it can greatly alter the results, so be sure to alert the lab tech and your doctor. You may be asked to have the blood drawn all over again.

Intermittent fasting? Yes, you can drink black coffee (or tea or pretty much any non-caloric beverage) if you’re doing intermittent fasting (IF). IF is based on a concept called “time-restricted feeding” in which you take in calories only during a small window of time each day. But black coffee does not contain calories, so drinking it won’t break your fast. Now, if you add cream or sugar, then you’ve blown your fast because those things contain calories.

When you’re asked to fast for medical reasons, it’s important to follow your doctor’s specific instructions – even if that means no coffee – because breaking the fast could seriously jeopardize your health. But if you’re fasting to lose weight or just because you think it’s a healthier lifestyle, you don’t have to give up coffee. In fact, you can consider it a little indulgence that might help you get through the fasting period more easily!

WebMD Blog
© 2020 WebMD, LLC. All rights reserved.
Blog Topics:

More from the Public Health Blog

View all posts on Public Health

Latest Blog Posts on WebMD

View all blog posts

Important: The opinions expressed in WebMD Blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. Blogs are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatments or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service or treatment.

Do not consider WebMD Blogs as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.

Read More