The Best Time to Drink Coffee
Before you blearily reach for that mug, just know this—timing is everything, especially if you have diabetes.
The moment my alarm goes off, my brain immediately dials in on one thing: the hot cup of coffee brewing in the kitchen. That familiar jolt of caffeine is just the thing I need to get up and get going, especially after a poor night of sleep or early on a Monday morning. Statistics show that I’m not alone in this–—64% of Americans drink coffee every single day.
If you, like me, tend to reach for that cup of joe first thing (think: within one hour after waking from a restless night of sleep), I have some bad news: A new study in the British Journal of Nutrition found that drinking black coffee (which revs up your metabolism) before breakfast and after a sleepless night can mess with your blood sugar levels. This may be especially problematic for people with impaired glucose tolerance or diabetes.
One possible solution according to Harry Smith, a Ph.D. student at the University of Bath in England and principal author on this new report is having your coffee with or after breakfast rather than before. Harry Smith, a Ph.D. student at the University of Bath in England and principal author on this new report, explains, “Based upon the findings, it may be best to wait until you have had breakfast and the meal has had a chance to ‘go down,’ so to speak, in order to avoid any crossover between the metabolic effects of caffeine and the metabolic response to the breakfast meal.”
Coffee & Metabolism
Caffeine is a stimulant, a substance that speeds up certain processes in your body. This includes your nervous system (which helps your brain “wake up”) and your resting metabolic rate. Some research suggests that coffee might help with weight management, due to its metabolism-boosting and appetite-suppressing qualities.
The effect of coffee on diabetes and prediabetes is a little less clear. “In clinical practice, we do see some patients react quite dramatically to coffee intake with significant spikes in glucose, while others have little to no effect,” says Kashif M. Munir, M.D., medical director of the University of Maryland Center for Diabetes & Endocrinology at the UM Medical Center Midtown Campus in Baltimore (who was not affiliated with the British Journal of Nutrition research).
This may have to do with the fact that people metabolize coffee differently. Multiple studies have shown that a gene called CYP1A2, which occurs in different variations in different people, may play a role in the speed at which someone’s body metabolizes coffee. This could help explain why your friend can down four cups per day while just one cup makes you feel jittery.
Blood Sugar Control
There’s another potential explanation for why coffee spikes blood sugar… everyone’s blood glucose levels are slightly higher in the morning to give the body energy. Dr. Munir explains that this heightened insulin resistance, combined with the stimulant effects of caffeine, could be the reason the British Journal of Nutrition study participants experienced a higher-than-normal spike in blood sugar after eating breakfast.
While this may be NBD for the average person, it can spell disaster for people who already struggle with blood sugar control. But before you freak out, there are ways to drink your coffee in a healthier way.
4 Tips for Changing Your Coffee Routine
To hack your body’s natural metabolism and keep your blood sugar in check, try these tips—no matter what time you reach for that cup.
Add some calories to your coffee. Adding milk, cream, or a non-dairy alternative to your coffee may create what Smith calls the “second meal effect,” where “the metabolic response to the calories now in the coffee ‘primes’ our metabolism for the second meal (breakfast).” This may help slow the body’s absorption of blood sugar.
Have your coffee with breakfast. Just like the “second meal effect,” this might allow your body to process the caffeine at the same time it processes calorie-dense food. (Or, as this study’s findings denoted, try drinking coffee after you put food in your system.) Still, this approach may not be a foolproof solution. “Whether drinking coffee after breakfast or using cream to dilute its effects makes a difference in glucose levels is still unknown,” Munir says.
Cut back on sweeteners. Love a sweet drink in the mornings? Just make sure it doesn’t contribute to a blood sugar crash. “Beware of flavored coffee creamers that may raise your blood sugar,” says Angela Ginn-Meadow, senior education coordinator at the University of Maryland Center for Diabetes & Endocrinology at the UM Medical Center Midtown Campus in Baltimore. “Patients should see how their coffee choice affects their blood sugar.” Here’s an easy way to do that: “Monitor your blood sugar before drinking the coffee and then two hours after,” Ginn-Meadow suggests. If it significantly impacts your blood pressure reading, try changing the ingredients you put in it.
Try a lower-caffeine version of your go-to drink. Hooked on super strong coffee? It might be time to dial it back a bit. Try slowly backing off your daily caffeine consumption (you can replace half the grounds with decaf to keep your ritual intact). The USDA Dietary Guidelines note that 400mg of coffee per day, or about four cups, is a safe amount for most people. But everyone is different, and your best bet is to trust your body.
There is no “perfect” coffee routine that works for everyone, so don’t be afraid to try a few different approaches to figure out the best game plan. If your morning cup of java is making you feel anxious, fatigued, or headachy (all signs your body isn’t reacting to it well), you may find that just a few small changes can lead to more clear-headed, enjoyable mornings.
- Coffee Drinking Survey: Reuters. (2018). “Americans are drinking a daily cup of coffee at the highest level in six years: survey.” reuters.com/article/us-coffee-conference-survey/americans-are-drinking-a-daily-cup-of-coffee-at-the-highest-level-in-six-years-survey-idUSKCN1GT0KU
- Coffee & Glucose Control Study: British Journal of Nutrition. (2020). “Glucose control upon waking is unaffected by hourly sleep fragmentation during the night, but is impaired by morning caffeinated coffee.” pubmed.ncbi.nlm.nih.gov/32475359/
- Coffee & Metabolic Rate: Obesity Reviews. (2011). “The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta‐analysis.” onlinelibrary.wiley.com/doi/full/10.1111/j.1467-789X.2011.00862.x
- Coffee & Weight Control: The Journal of Nutrition. (2020). “Regular Coffee Consumption Is Associated with Lower Regional Adiposity Measured by DXA among US Women.” korr.com/wp-content/uploads/faq-12-2.pdf
- Coffee Genetic Metabolism: Journal of the American Medical Association. (2006). “Coffee, CYP1A2 genotype, and risk of myocardial infarction.” pubmed.ncbi.nlm.nih.gov/16522833/
- USDA Dietary Guidelines on Caffeine: U.S. Department of Agriculture. (2020.) “2015-2020 Dietary Guidelines: Answers to Your Questions.” choosemyplate.gov/node/5679