Health

What Happens When You Drink Coffee on an Empty Stomach

September 7, 2025
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Coffee is one of the most popular beverages worldwide, offering several health benefits, including increased alertness, improved athletic performance, and enhanced brain function. Many people can safely drink coffee on an empty stomach, but others may experience gastrointestinal discomfort and other symptoms.

1. Increased Stomach Acidity and Risk of Heartburn

Coffee is an acidic beverage, and drinking it on an empty stomach may cause the stomach to produce more acid. Having an excess of stomach acid may irritate the stomach lining and cause heartburn.

Drinking coffee may stimulate an increase in acid production in the stomach. When the acid travels up the esophagus, it causes a burning sensation in the chest, known as heartburn or reflux. Caffeine also relaxes the lower esophageal sphincter, a ring of muscle between your esophagus (food tube) and stomach, which can increase reflux.

People with a history of heartburn, gastrointestinal reflux disease (GERD) (chronic heartburn), or irritable bowel syndrome (IBS) may need to use caution when drinking coffee on an empty stomach. However, there is no current research to suggest that drinking coffee on an empty stomach causes or increases the risk of developing GERD.

If you experience heartburn when drinking coffee, try eating a snack or a small meal before enjoying your cup of coffee. Having food in your stomach may help prevent the production of more stomach acid.

A 2014 study found that drinking light-roasted coffee may cause more of a stomach acid increase than drinking dark-roasted coffee. If you notice heartburn symptoms with coffee, consider switching to a darker roast. 

2. Faster Caffeine Absorption

Drinking coffee on an empty stomach may cause your body to absorb the caffeine in it faster. Caffeine is a natural stimulant and may cause feelings of anxiety or jitteriness. Drinking coffee with food may slow the absorption and lower the risk of experiencing caffeine side effects. 

Drinking excessive amounts of caffeine can lead to restlessness, a racing heart rate, and anxiety. It may also cause headaches and raise blood pressure. 

Drinking coffee has been linked with an increased risk of anxiety. It is important to note that the studies that have found a link between coffee and anxiety are based on people who drink more than six cups per day. 

Most healthcare providers recommend limiting your caffeine intake to 400 milligrams per day. That is the amount found in four to five cups of coffee. Caffeine’s effects can last up to seven hours in adults, so try not to drink coffee on an empty stomach near bedtime. 

Coffee in Pregnancy

The caffeine in coffee can cross the placenta and impact fetal health. Most healthcare providers recommend that pregnant people limit their caffeine intake to one to two cups of coffee per day. 

3. Digestive Issues

Some people may experience digestive issues when drinking coffee on an empty stomach. Symptoms may include bloating, cramping, nausea, heartburn, or diarrhea.

Some people may experience an increased urge to have a bowel movement. People with IBS may notice gastrointestinal discomfort or diarrhea after drinking coffee. 

4. Hormonal Changes

Drinking coffee on an empty stomach may cause hormonal changes in the body. The caffeine in coffee stimulates the release of cortisol, commonly referred to as the stress hormone.

Cortisol regulates metabolism and blood pressure. Increased levels of cortisol may increase the risk of anxiety, irritability, and sleep problems. Over time, high cortisol levels can lead to heart disease and bone loss.

Fortunately, the increase in cortisol production from caffeine does not appear to be significant and has not been linked with any health problems. 

Coffee and Nutrient Absorption

Some research studies have found that drinking coffee may interfere with the body’s ability to absorb certain nutrients. Drinking coffee with iron-rich foods may impact how much iron the body absorbs. Fortunately, drinking coffee on an empty stomach does not affect nutrient absorption. 

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Poole R, Kennedy OJ, Roderick P, Fallowfield JA, Hayes PC, Parkes J. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes [published correction appears in BMJ. 2018 Jan 12;360:k194. doi: 10.1136/bmj.k194.]. BMJ. 2017;359:j5024. doi:10.1136/bmj.j5024

  2. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: a comprehensive review. Front Psychiatry. 2017;8:80. doi:10.3389/fpsyt.2017.00080

  3. Nehlig A. Effects of coffee on the gastro-intestinal tract: a narrative review and literature update. Nutrients. 2022;14(2):399. doi:10.3390/nu14020399

  4. Kim J, Oh SW, Myung SK, et al. Association between coffee intake and gastroesophageal reflux disease: a meta-analysis. Dis Esophagus. 2014;27(4):311-317. doi:10.1111/dote.12099

  5. Mehta RS, Song M, Staller K, Chan AT. Association between beverage intake and incidence of gastroesophageal reflux symptoms. Clin Gastroenterol Hepatol. 2020;18(10):2226-2233.e4. doi:10.1016/j.cgh.2019.11.040

  6. Johns Hopkins. 5 foods to avoid if you have IBS.

  7. National Institute of Diabetes and Digestive and Kidney Diseases. Acid reflux (GER & GERD) in adults.

  8. Rubach M, Lang R, Bytof G, et al. A dark brown roast coffee blend is less effective at stimulating gastric acid secretion in healthy volunteers compared to a medium roast market blend. Mol Nutr Food Res. 2014;58(6):1370-1373. doi:10.1002/mnfr.201300890

  9. Rodak K, Kokot I, Kratz EM. Caffeine as a factor influencing the functioning of the human body-friend or foe?. Nutrients. 2021;13(9):3088. doi:10.3390/nu13093088

  10. Barcelos RP, Lima FD, Carvalho NR, Bresciani G, Royes LF. Caffeine effects on systemic metabolism, oxidative-inflammatory pathways, and exercise performance. Nutr Res. 2020;80:1-17. doi:10.1016/j.nutres.2020.05.005

  11. Lee MJ, Choi HA, Choi H, Chung CS. Caffeine discontinuation improves acute migraine treatment: a prospective clinic-based study. J Headache Pain. 2016;17(1):71. doi:10.1186/s10194-016-0662-5

  12. Richards G, Smith A. Caffeine consumption and self-assessed stress, anxiety, and depression in secondary school children. J Psychopharmacol. 2015;29(12):1236-1247. doi:10.1177/0269881115612404

  13. Food and Drug Administration. Spilling the beans: how much caffeine is too much?.

  14. American College of Obstetrics and Gynecology. Moderate caffeine consumption during pregnancy.

  15. Nieber K. The impact of coffee on health. Planta Med. 2017;83(16):1256-1263. doi:10.1055/s-0043-115007

  16. Taraszewska A. Risk factors for gastroesophageal reflux disease symptoms related to lifestyle and diet. Rocz Panstw Zakl Hig. 2021;72(1):21-28. doi:10.32394/rpzh.2021.0145

  17. Lovallo WR, Whitsett TL, al’Absi M, Sung BH, Vincent AS, Wilson MF. Caffeine stimulation of cortisol secretion across the waking hours in relation to caffeine intake levels. Psychosom Med. 2005;67(5):734-739. doi:10.1097/01.psy.0000181270.20036.06

  18. National Institute of Diabetes and Digestive and Kidney Diseases. Cushing’s syndrome.

  19. Papakonstantinou E, Kechribari I, Sotirakoglou Κ, et al. Acute effects of coffee consumption on self-reported gastrointestinal symptoms, blood pressure and stress indices in healthy individuals. Nutr J. 2016;15:26. doi:10.1186/s12937-016-0146-0

  20. von Siebenthal HK, Moretti D, Zimmermann MB, Stoffel NU. Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women. Am J Hematol. 2023;98(9):1356-1363. doi:10.1002/ajh.26987

Carrie Madormo

By Carrie Madormo, RN, MPH

Madormo is a health writer with over a decade of experience as a registered nurse. She has worked in pediatrics, oncology, chronic pain, and public health.

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