Is It Bad to Drink Coffee on an Empty Stomach? A Dietitian Separates Fact From Fiction

But the evidence is mixed. Some studies have found that drinking coffee is associated with a higher chance of having reflux. Other large reviews found no link between coffee and reflux. 

The American Society for Gastrointestinal Endoscopy considers coffee a possible “trigger food” for reflux. They suggest keeping a food diary to track your symptoms and see if coffee makes symptoms worse. But they say that if coffee doesn’t bother you, it’s fine to drink. 

Most studies look at drinking coffee with meals or after meals, not on an empty stomach. But, since drinking coffee on an empty stomach means that there’s less food to “reflux,” it might be even less likely to cause symptoms. 

What matters is how your body responds. Keep track of your symptoms. If you feel fine drinking coffee on an empty stomach, it’s OK to make that part of your morning ritual. 

Ulcers

The caffeine in coffee causes your stomach to release acid. Too much stomach acid can lead to the development of ulcers, sores on the lining of your stomach or small intestine. This is why many people believe that drinking coffee can lead to ulcers. 

But research doesn’t support this belief. Multiple studies have found that there’s no link between drinking coffee and getting ulcers. In fact, according to the American College of Gastroenterology, diet doesn’t cause ulcers. 

And drinking coffee on an empty stomach wouldn’t be expected to increase your chance of having an ulcer. In fact, when you eat food, your stomach produces acid as part of the normal digestive process. So an empty stomach would have even less acid than a stomach with food. This means that drinking coffee on an empty stomach is unlikely to cause ulcers. 

Jitters/anxiety

Caffeine is known to contribute to anxiety. Caffeine from coffee is rapidly absorbed into your bloodstream. As mentioned above, caffeine is absorbed even faster if it’s consumed without food. This helps explain why consuming coffee on an empty stomach may lead to increased feelings of the “jitters” or other symptoms of anxiety. (Consuming caffeine with food can cause similar symptoms, but usually they won’t be as severe.) 

For this reason, you may choose to limit your caffeine intake. Or pair it with some food. This will help slow the absorption and reduce possible negative effects.

Exercise performance

When you drink coffee before a workout, it can help you exercise better. Drinking coffee has been shown to improve:

• Muscle strength

• Endurance

• Speed  

And research has found that this exercise-boosting effect is even more pronounced if you drink your preworkout coffee on an empty stomach. So if you like to start your day with a workout, grab a cup of coffee first — even before breakfast — to give an extra boost to your exercise. 

Diarrhea

You may already know that coffee can help you poop. Coffee sends signals to your gut to increase contractions and help move food along. So it can be a helpful drink to try if you’re constipated. 

But does coffee cause diarrhea? Some studies suggest it doesn’t cause diarrhea in otherwise healthy people. But if you have irritable bowel syndrome (IBS), drinking coffee can make your symptoms worse, and may make you stool too often. 

If you’re prone to loose stools or diarrhea, pay attention to what happens when you drink coffee — on a full or empty stomach — to see if you should lower your intake. 

Malabsorption

Coffee contains antinutrients, including oxalates and tannins. Antinutrients are plant compounds that can block your body from absorbing certain nutrients. So, some people believe that drinking coffee can lead to problems absorbing these nutrients. 

It’s true that caffeine and antinutrients in coffee together may reduce the body’s ability to absorb nutrients, such as calcium, magnesium, and iron. Research suggests that drinking coffee with a meal reduces iron absorption by 24% to 73%. 

For most people, this effect will be minimal. But some researchers recommend that for this reason, pregnant people should limit coffee consumption and avoid drinking coffee with meals. 

But drinking coffee on an empty stomach specifically should have a minimal effect on nutrient absorption. If no food is consumed with the coffee, there are no nutrients to hamper. So, from a nutrient perspective, it might actually be better to consume coffee on an empty stomach. 

Weight gain

There’s no evidence that coffee on its own will contribute to weight gain. In fact, caffeine from coffee can actually boost your metabolism. Studies show that consuming caffeine may help promote weight loss and reduce body fat. And it doesn’t seem to matter whether the caffeine is consumed on an empty stomach or not.

But the relationship between coffee and weight is complex. Many coffee drinks are loaded with excess calories, fat, and added sugar — all of which can contribute to weight gain. So it’s important to try to choose healthy coffee drinks, and drink them as part of a balanced diet. 

Changes to gut bacteria

Multiple studies have shown that drinking coffee can affect the types of bacteria in your gut microbiome — the collection of microorganisms living in your digestive tract. But there are trillions of bacteria lining your gut, and scientists are trying to understand them better. 

At this point, it’s clear that drinking coffee affects your gut’s bacteria. What’s not clear is whether these changes are positive or not.

Energy levels

Many people drink coffee not just for the taste, but for the energy boost that caffeine can provide. Caffeine increases energy levels and alertness. Depending on the person, blood levels of caffeine can peak between about 15 minutes and 2 hours after it’s consumed. 

Eating food slows down the rate at which caffeine gets absorbed. So, as mentioned above, drinking coffee on an empty stomach means you’ll probably feel that energy boost more quickly and/or in a more pronounced way. 

But everyone’s body works differently. Other factors, like your weight, also affect how quickly you’ll feel that jolt of energy.