What You Don't Know About Caffeine

Caffeine is a regular part of many people’s daily schedule, and because it is a substance that contains no calories, it is often overlooked when considering what can affect blood sugar. You often see coffee (with nothing added to it) referred to as a “free” food, which may lead you to think it’s fine to have as much as possible.

Unlimited caffeine, even straight black coffee, is not safe for anyone. The recommended daily allowance for caffeine is 400 mg, and an 8 oz coffee (aka, about the amount that fits in a mug), contains around 130 mg. More than three cups of coffee a day is not necessarily safe for anyone.

People living with diabetes have even more of a reason to keep an eye on caffeine consumption. Caffeine can alter the way glucose is processed and insulin is regulated, leading to higher blood sugar. In other words, caffeine may cause a higher spike in blood sugar from consuming the same amount of carbohydrate consumed without caffeine. This is notable because caffeine is almost always consumed with carbohydrate: sugar added to coffee and tea, sodas, and breakfast served alongside coffee are some examples of this.

People who consume large amounts of coffee (or other caffeinated beverages) each day might find it very difficult to cut these drinks out, due to the addictive nature of caffeine. If you drink more than the recommended safe level, cutting back should definitely be a priority. Similarly, if you regularly drink caffeinated beverages daily, especially if you drink more than two every day, and you feel as if you have less control over your blood sugar than you should, decreasing the amount of caffeine you drink may be helpful. If you try drinking less caffeine and your blood sugar control improves, then it’s very possible that caffeine was the culprit.

If you drink caffeinated beverages and want to cut back, here are some tips:

  • Phase out some caffeinated beverages and switch them for decaf. Maybe switch coffee or tea to a blend of decaf and regular within each drink or change some around so half are regular and half are decaf.

  • If you enjoy tea, green or herbal teas have less caffeine than black tea.

  • Don’t use soda to quench thirst, because it’s very easy to chug too much. Reach for water instead as a solution to thirst.

  • Aim to add no sugar to your morning beverage; it may be easier to phase the amount of sugar out over several days so it isn’t as noticeable.