Always Drink Coffee On An Empty Stomach? What Experts Want You To Know

Drinking coffee is linked to plenty of health benefits, from reducing the risk of liver disease to boosting cognitive health. However, how you drink coffee can get in the way of some of its perks. What about drinking coffee on an empty stomach? While some swear by drinking a cup of coffee first thing in the morning, others warn that drinking coffee on an empty stomach can wreak havoc on your hormones, stomach, and more. 

One difference is that you might absorb caffeine more rapidly1 when drinking coffee on an empty stomach. When consuming coffee with food or even alongside a calorie-containing beverage, like a protein shake, the absorption of caffeine will be delayed because gastric emptying slows after eating nutrients2 like protein and fat.

If you drink a cup of coffee on an empty stomach, you're likely to absorb the caffeine much quicker, which may lead to some side effects, especially in people who are sensitive to caffeine to begin with.

Drinking coffee on an empty stomach may also trigger or worsen symptoms of gastroesophageal reflux disease (GERD) by decreasing the pressure of the lower esophageal sphincter (LES)3. The LES is a ring-like muscle at the lower end of the esophagus that prevents swallowed food from flowing back from the stomach and protects the esophagus from stomach acid. 

"Coffee, which is an acidic beverage, can cause alterations in gastrointestinal motility and increase acid production in the stomach. Coffee also relaxes the lower esophageal sphincter and triggers heartburn, so patients with heartburn may want to avoid drinking coffee on an empty stomach if they find that it triggers their symptoms," Ravella explains.

Another common argument against drinking coffee on an empty stomach is that it can negatively impact hormone levels, specifically the stress hormone cortisol. Again, research on this specific relationship is limited, though existing studies show that regular coffee intake doesn't seem to have much of an impact on cortisol levels. 

For example, a 2023 study that included 148 people found no significant effects of regular caffeine use5 on baseline cortisol or reactivity. However, when consumed under stressful conditions, caffeinated beverages, like coffee, may increase cortisol response6 to the stressor.

As mentioned above, caffeinated coffee intake doesn't seem to have a significant impact on cortisol levels in general. A 2016 study published in BMC Nutrition found that consuming 200 milliliters of coffee containing 160 milligrams of caffeine had no impact on cortisol levels7, indicating that coffee ingestion did not increase stress levels under non-stressful conditions.

If you drink coffee before a meal, it may suppress your appetite. A 2017 review published in the International Journal of Food Sciences and Nutrition found that consuming caffeine four hours to 30 minutes before a meal could help reduce calorie intake9. However, other studies have shown that drinking coffee alongside a meal10 could also help reduce calorie intake, which indicates that caffeinated coffee may help reduce energy intake in general.

While some people may be able to tolerate a cup of coffee on an empty stomach, others may find that drinking coffee before eating triggers nausea, reflux, or anxiety. 

People with digestive conditions like GERD, acid reflux, or IBS may be particularly sensitive to coffee and may find that drinking it alongside a mixed meal works best for them. Additionally, those with other medical conditions, like anxiety, arrhythmias, high blood pressure, and insomnia, may want to cut back on their caffeine intake in general, as caffeine may worsen symptoms in these populations.

However, others may find that drinking a cup of coffee on an empty stomach first thing in the morning gives them energy and stimulates a healthy bowel movement. People practicing intermittent fasting may also find that sipping on a cup of black coffee during their fasting window makes the fast more tolerable.

If you find that drinking coffee on an empty stomach first thing in the morning upsets your system, you can also try delaying your caffeine intake by 90 to 120 minutes. Some health experts even say that doing so can also support your mood and energy levels.

Cortisol levels fluctuate throughout the day and night, with the lowest cortisol concentration occurring around midnight. After that, cortisol keeps rising into the morning hours and is usually at its peak around 9 a.m13. 

Delaying caffeine intake may give your cortisol levels time to drop and give your body time to wake itself up naturally before introducing a stimulating substance. However, this depends on when you wake up, your work and sleep schedule, and more.

If you find that drinking coffee on an empty stomach leads to any negative side effects, try drinking it with food, drinking less of it, or delaying your intake until 90-120 minutes after you wake up.

The most important thing to remember is that coffee shouldn't be used as a replacement for breakfast. Skipping breakfast can have negative consequences on your energy, appetite, and metabolic health in the long run. So even if you prefer to drink your coffee solo, be sure to follow it up with a well-balanced, protein-rich breakfast at some point.

Existing evidence suggests that, for most people, drinking coffee on an empty stomach is A-OK. That said, people who are sensitive to caffeine and those with certain health conditions, like GERD, may want to cut back on coffee or pair theirs with a meal to reduce its stimulating effects.