What Happens to Your Blood Sugar When You Drink Coffee

Your blood sugar naturally fluctuates throughout the day. “Levels rise after meals for everyone because carbohydrates break down into glucose,” says Kathleen Benson, CSSD, CPT, RDN. In people with insulin resistance or diabetes, these increases may be higher and last longer because the body doesn’t respond to insulin as efficiently or doesn’t produce enough of it, Benson explains.

“For most people, blood sugar levels are lowest in the morning after fasting overnight and rise after meals as your body digests and absorbs carbohydrates,” adds Lauren Manaker, M.S., RDN, LD, CLEC, CPT. Since many of us reach for a cup (or two) of coffee in the morning, you may wonder whether your daily brew is affecting your blood sugar levels at the start of each day. Our experts take a deep dive into how your morning java may affect your blood sugar.

How Coffee Affects Your Blood Sugar

“Coffee on its own typically doesn’t cause a significant rise in blood sugar itself,” Manaker says. It’s the other add-ons, like sugary syrups and certain sweeteners, that can lead to a temporary spike in blood glucose, Manaker notes. “If you’re drinking coffee after a meal, the impact on blood sugar is likely minimal, especially if the meal includes protein and healthy fats.”

Those who are caffeine-sensitive and don’t have diabetes may also see a more dramatic increase in blood sugar compared to others. “Coffee can raise blood sugar for some people because caffeine can trigger hormones that tell the liver to release extra glucose,” Benson says., “This doesn’t happen to everyone, and the effect depends on how sensitive someone is to caffeine and how much they drink.”

4 Factors That Can Affect How Coffee Impacts Your Blood Sugar

1. The Type of Sweetener You Use

A recent study suggests that drinking a few cups of black coffee daily is associated with a lower risk of developing type 2 diabetes. However, that isn’t the case when added sugars or even artificial sweeteners are swirled in. “Added sugars—including table sugar, flavored syrups, honey and agave—can raise blood sugar because they’re quickly absorbed by the body,” Benson says. 

That said, if you do prefer something a little sweet in your morning cup of joe, using certain sugar-free sweeteners is still a better option, the experts say.

“Sugar alcohols, like in ‘skinny’ syrups, may cause a smaller rise in blood sugar, while nonnutritive sweeteners like stevia don’t raise blood sugar at all,” Benson says. To lessen the impact, Benson offers a few suggestions: gradually reduce added sugar, switch to half-syrup or use stevia to keep sweetness without the spike.

2. The Type of Creamer You Add

There are so many types of creamers out there—and each can have a different impact on your blood sugar levels. 

“Sweetened creamers, especially flavored ones, often contain added sugars that raise blood sugar,” Benson says. “Even half-and-half or whole-milk creamers can raise blood sugar slightly in larger amounts due to natural lactose.” (Lactose is the naturally occurring sugar in dairy milk.)

While nondairy creamers lack lactose, some make up for it with added sugars, Manaker says, which can lead to temporary spikes in blood sugar, too. 

Your move: Stick to 1 to 2 tablespoons of unsweetened creamers, like heavy cream, half-and-half or unsweetened plant-based milk, Benson says. 

3. Drinking Coffee on an Empty Stomach

“Drinking caffeine on an empty stomach can cause sharper blood sugar rises because there’s no protein, fat or fiber to buffer the stress-hormone response,” Benson says. 

Let’s break this down: Caffeine activates the body’s fight-or-flight response, increasing the release of stress hormones like cortisol, epinephrine and norepinephrine. These hormones signal the liver to release stored glucose, which can lead to a rapid spike in blood sugar.,

“If you’re sipping coffee solo, you might miss out on the blood sugar–stabilizing benefits of protein,” Manaker says. “Pairing your coffee with a protein-rich snack or meal can help keep your blood sugar more stable.”

Consider drinking your morning java alongside two scrambled eggs, one serving of Greek yogurt, or with a small bowl of cottage cheese and fruit, Benson says. Including protein at meals is often recommended to help stabilize post-meal glucose levels.

4. Your Sensitivity to Caffeine

“Some people are more sensitive to caffeine, which can temporarily raise stress hormones like cortisol and lead to higher blood sugar levels,” Manaker says., “If this sounds like you, try limiting your coffee intake or switching to decaf.”

If you’re someone who doesn’t typically sleep well or works a high-stress job, you may already have elevated cortisol levels, Benson notes. “Adding caffeine on top can exaggerate the blood-glucose rise,” she says. 

Ease the impact by adopting sleep-hygiene strategies, drinking plenty of water and avoiding caffeine when you’re already stressed. 

Other Ways to Manage Your Glucose Levels

You can enjoy coffee without the temporary spike in blood sugar. Follow these expert–backed strategies for keeping your blood sugar levels steady. 

• Stay active. “Regular physical activity helps your body use insulin more effectively, keeping blood sugar levels in check,” Manaker says. “Even a 10-minute walk after meals can make a difference.” Benson concurs, adding: “Light movement helps muscles use glucose more efficiently and reduces post-meal spikes.”
• Eat consistent meals, especially earlier in the day. “Skipping meals can impair insulin sensitivity, leading to higher post-meal rises. It’s also been associated with higher long-term diabetes risk,” Benson says. “Most people see better blood sugar stability when they keep coffee as part of a balanced morning routine, not a replacement for breakfast.”  

Our Expert Take

TL;DR: If you’re worried about your blood sugar levels, you don’t need to stop enjoying your morning cup of coffee—many people look forward to that part of their day. Just keep in mind the factors that might adversely affect your glucose levels when you drink your cup of joe. If you have diabetes and you’re monitoring your blood glucose levels throughout the day, or you tend to feel jittery after your cup of java, you can ease any temporary blood sugar spikes by enjoying breakfast with your cup of coffee and staying active.