Rise and grind: Can you drink coffee on an empty stomach?

For many of us, our day doesn’t get started until we’ve had a cup of coffee—or two. Coffee is full of caffeine, a natural stimulant, which helps kickstart the day and gives us a quick boost in energy. While there are other benefits to drinking coffee (such as supporting weight loss and heart health), we most often reach for a coffee when we need to get going in the mornings.

Eating a well-balanced breakfast with your cup of coffee sets you up for a successful day. But sometimes if it’s a hectic morning, it’s easy to just grab a cup of coffee on an empty stomach. The good news is that drinking coffee on an empty stomach isn’t necessarily bad for you, but it may cause some discomfort and side-effects throughout the day.

Have you ever been warned not to consume caffeine before bed? This is because an after dinner espresso may taste great in the moment, but it can keep you awake and disrupt your sleep-wake cycle. In the same way, if you drink too much coffee in the morning with little or no food, it can impact how you feel later on in the day.

What happens if you drink coffee on an empty stomach?

There are two primary bodily responses that can occur if you drink coffee on an empty stomach: digestive upset and a hormonal response.

Though coffee affects everyone differently, it can cause issues for our digestive system. It’s not uncommon for individuals to experience heartburn or a chest burning sensation, upset stomach, loose stools or even symptoms of a GERD flare up.

Coffee contains chlorogenic and citric acids. When consumed, these produce more acid in your stomach and can lead to discomfort in your digestive system. However, if you eat breakfast with your coffee, the stomach acid has some food to digest and will ease any adverse GI symptoms you may face.

Some other ways you can minimize coffee’s acidity is:

• Choose a darker roast
• If you're lactose intolerant, try using a dairy-free alternative such as almond or oat milk
• Try cold brew coffee. It has less acid but be aware it does contain more caffeine.

Not only does coffee on an empty stomach have potential gastrointestinal side effects, but coffee can also disrupt hormones in your body. Specifically, the “stress” hormone, otherwise known as cortisol.

What is cortisol?

Cortisol is commonly known as the “stress hormone.” But it’s an essential hormone that contributes to many of the body’s processes. For example, it:

• Aids in controlling your body’s metabolism
• Controls your body’s sleep and wake cycle
• Keeps inflammation at bay
• Regulates blood pressure
• Regulates blood sugar

Our cortisol levels fluctuate throughout the day and typically peak in the morning from 7 to 8 a.m.

The coffee and cortisol relationship: Does coffee cause stress?

Most of us like to enjoy our cup of coffee first thing in the morning. When we wake up, our cortisol levels are at their highest and continue to rise and peak for about 30 to 45 minutes.

If you drink coffee when your cortisol levels are at their highest, it can cause increased levels of this hormone, triggering more stress in our bodies. The effects of caffeine can be felt as soon as 15 minutes after consumption. For most, the level of caffeine stays in the body for much of the day and can sometimes take up to 10 hours to wear off.

The stimulating effects of coffee can rev up your system and while some enjoy this extra burst of energy to their system, others can start to feel anxious, irritable, stressed out or jittery. For women, cortisol levels can vary throughout the menstrual cycle. So, your caffeine consumption could affect you differently throughout the month.

Signs that you may have elevated cortisol levels include:

• Dehydration
• Dizziness
• Experiencing the “jitters”
• Headache
• Increase in blood pressure
• Nervousness
• Racing heart or abnormal heartbeat

If you find yourself facing these negative side effects of coffee, eating a snack can decrease the absorption rate of caffeine and a nutritious breakfast can help balance your cortisol levels throughout the day.

If you find your body is sensitive to caffeine, try pairing it with a protein-packed breakfast full of nutrients or exploring alternative options like decaffeinated coffee. Be mindful of how caffeine impacts your health so you can enjoy your coffee and feel your best throughout the day.

Looking for expert advice on your daily nutritional needs? Connect with a registered dietitian today.