The Impact of Caffeine on Blood Sugar Levels

Lindsay Cohen, RDN

Credit: Mama-Betes

Caffeine is a natural stimulant that works by blocking adenosine, a brain chemical that makes you feel tired. Blocking this chemical leads to increased alertness and energy.

For many of us, caffeine is a daily ritual. We rely on it to wake up, improve our focus and combat the dreaded afternoon slump. It’s in our morning coffee, midday tea and even a piece of chocolate. But if you are managing diabetes, prediabetes or insulin resistance, you are probably wondering whether caffeine has any impact on your blood sugar levels.

The short answer is, it’s complicated. The effect of caffeine on blood sugar levels is highly individualized. Some people see a noticeable rise when they consume caffeine, while others experience little to no impact.

This article will explore the science behind caffeine and blood sugars, the factors that influence it and practical tips for managing your caffeine intake.

Why Caffeine Might Increase Blood Sugar

Caffeine is a central nervous system stimulant, and its job is to put the body on high alert. It does this by triggering a hormonal response designed to prepare the body for a fight-or-flight scenario, which prompts the release of adrenaline. Adrenaline signals the liver to release stored glucose into the bloodstream, providing a quick burst of energy. While this is helpful in a stressful situation, it can lead to an unwanted blood sugar spike when all we are doing is enjoying a cup of coffee.

In addition, some studies suggest that caffeine can also temporarily decrease insulin sensitivity. Insulin is the hormone that helps your body’s cells absorb sugar from the bloodstream. When your cells become less sensitive to insulin, they don’t absorb sugar as efficiently, which can cause blood sugar levels to rise.

Research on this topic is ongoing, and results are mixed. This is because the effect of caffeine varies so much from person to person.

Factors That Influence Caffeine’s Impact

Why do some people see a blood sugar spike with caffeine while others don’t? Several factors likely play a role:

• Individual health status: People with prediabetes or diabetes are more likely to experience a blood sugar increase after consuming caffeine. Their bodies are already working hard to manage blood sugars, and the added challenge from caffeine can make it more difficult to maintain stable levels. Those without a history of diabetes or insulin resistance are less likely to notice a blood sugar response from caffeine.
• Habitual intake: Your body can build a tolerance to caffeine. Regular, heavy coffee drinkers may experience less of a blood sugar response than someone who consumes caffeine only occasionally.
• Type of beverage: Not all caffeinated drinks are created equal. The most significant blood sugar spikes often come from the added ingredients, not just the caffeine itself.
  • Black coffee or unsweetened tea typically has the lowest impact.
  • Lattes, sugary coffees, energy drinks and sodas are often loaded with sugar, syrups or milk, which can cause a significant blood sugar increase regardless of the caffeine.
• Timing: Consuming caffeine on an empty stomach might lead to a more significant blood sugar response than having it with a meal.

Determining Caffeine’s Impact on Your Blood Sugar

The best way to understand your personal response to caffeine is to monitor your blood sugar patterns. Try checking your blood sugar or monitoring your continuous glucose monitor (CGM) before you have a caffeinated drink and then again one to two hours afterward.

To isolate the effect of caffeine, try drinking your coffee or tea black, or with a sugar-free sweetener and a splash of milk. This removes the variable of added carbohydrates, allowing you to truly see how the caffeine itself impacts you. This will help you identify any patterns.

6 Recommendations for Managing Caffeine and Blood Sugar

Consider the following:

• Choose low-sugar options: Be mindful of added sugars. Opt for black coffee or unsweetened tea. When ordering from a coffee shop, ask for sugar-free syrups and avoid sweetened creamers.
• Limit intake: If you notice that caffeine causes significant blood sugar fluctuations, consider limiting your intake or choosing decaffeinated options. Herbal teas are great alternatives.
• Stay hydrated: Caffeine increases urine production. Staying well hydrated with water throughout the day is important for overall health and can also support blood sugar management.
• Pair with food: If you notice blood sugar fluctuations, try consuming caffeine with a balanced meal that contains fiber, protein and healthy fats. This can help reduce the blood sugar response.
• Eat a balanced diet: An overall diet rich in fiber, protein and complex carbohydrates provides a stable foundation for blood sugar control, which can help reduce the potential impact of caffeine.
• Talk to your health care team: Your endocrinologist, dietitian or diabetes educator is your partner. They can help you interpret your blood sugar numbers and help you create a personalized strategy that allows you to enjoy caffeine safely.

The relationship between caffeine and blood sugar is complex and highly individualized. While some people find that caffeine increases blood sugar levels, others see minimal or no effect, which highlights the importance of paying attention to your own individual response.