Is Drinking Coffee on an Empty Stomach Harmful? Here’s What the Research Says…

by | Jul 10, 2025 | Healthcare | 0 comments

It’s a common belief that drinking coffee on an empty stomach is harmful—but for most people, that’s not necessarily true. According to experts like registered dietitian Anthony DiMarino, RD, LD, and resources such as the Cleveland Clinic Health Essentials and GoodRx, there is no conclusive evidence that coffee consumed without food leads to long-term health issues for the general population. 

However, some individuals may experience short-term effects when drinking coffee before eating. Here’s what you should know: 

Potential Digestive Effects 

  •  Increased Stomach Acid: Coffee naturally stimulates gastric acid production. This may aid digestion in some but may relax the lower esophageal sphincter, potentially causing  heartburn, acid reflux, or discomfort in others—especially those with GERD or sensitive stomachs. Scientific evidence is mixed: some studies link coffee to reflux; others find no association. 
  •  Stomach Lining Irritation: Compounds in coffee, such as chlorogenic acids, can irritate the stomach lining in susceptible individuals. 
  •  Digestive Condition Flares: People with IBS or other gut sensitivities may notice increased symptoms like cramping or diarrhea due to coffee’s stimulatory effects on the intestines.
  • Gut Microbiome: Coffee has been shown to shift the composition of gut bacteria. The implications of these changes are still being researched. Whether this is “good” or “bad” remains unclear – more studies are needed. 

Hormonal and Blood Sugar Considerations 

  •  Cortisol Spike: Coffee can increase cortisol, the body’s stress hormone—especially when consumed first thing in the morning. This may trigger feelings of jitteriness or anxiety in some individuals.
  • Blood Sugar Fluctuations: When consumed without food, caffeine is absorbed more quickly and may reduce insulin sensitivity, leading to short-term spikes and crashes in blood glucose.
  • Exercise Performance: Drinking coffee before exercise, especially on an empty stomach, can enhance performance, making it a popular natural pre-workout. Coffee may increase muscle strength, boost endurance and speed and enhance fat burning. 

 Important Individual Factors 

  •  Everyone Responds Differently: Some people tolerate coffee on an empty stomach without issue, while others may feel unwell. Monitoring your own response is key.
  • Symptom Management Tips:
  • Try eating a small snack before coffee. 
  • Add milk or a plant-based creamer to buffer acidity. 
  • Opt for low-acid or decaf varieties if needed. 
  • Myth Busting: Coffee does not cause ulcers. Most ulcers stem from H. pylori infections or chronic NSAID use—not coffee. 

Bottom Line 

For most people, drinking coffee on an empty stomach is not harmful. However, if you experience digestive discomfort, anxiety, or blood sugar swings, you may benefit from adjusting how and when you drink it.  

Morning is the most common time and fine for most people. If you’re sensitive to caffeine or prone to digestive issues, consider having a small snack first. Avoid late-day coffee if you’re prone to insomnia. Caffeine’s half-life can range from 2 to 12 hours, depending on the individual. Consider decaf in the afternoon or evening. 

As always, listen to your body and modify your habits to support your health. 

Sources:

Disclaimer:
The content provided in this article is for informational and educational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making any changes to your health regimen, starting new therapies, or discontinuing existing treatments. Mention of specific practices, therapies, or organizations does not constitute an endorsement. The views expressed are those of the author and may not reflect the policies or positions of any affiliated entities.