When you’re tracking your blood sugar levels with a continuous glucose monitor (CGM), it’s normal to see a rollercoaster-looking graph of little peaks and valleys throughout the day. And if there’s one place you’d expect to see changes in blood sugar, it’s when you eat. While it’s good to keep your blood sugar levels relatively stable (no sharp spikes!), your blood sugar level will naturally rise after you eat as sugar enters your bloodstream. If you’re wondering when your blood sugar will return to normal after eating — you’ve come to the right place. Here’s what you need to know about tracking your blood sugar after eating.

How your body handles sugar

During digestion, the carbohydrates you consume are broken down into sugar that is then released into your bloodstream. When this happens, your blood sugar levels rise, which signals to your pancreas that it’s time to produce insulin. Insulin’s job is to get that sugar out of your blood and into your cells so it can be burned for energy. (Any extra glucose that your body doesn’t need for energy at that moment is stored as glycogen in the liver and muscle or converted to fat.) Still, some sugar will stay in your blood, especially if your pancreas isn’t able to make enough insulin or the insulin it does produce isn’t able to do its job effectively, which is the case with uncontrolled diabetes. When too much sugar stays in the blood — you guessed it — your blood sugar levels will go way up.

How long after eating does blood sugar peak?

For those with diabetes, glucose levels typically hit their peak within 90 minutes of eating. This is how long it can take for your body to fully register the sugar that’s made its way into your bloodstream after you consume carbohydrates. 

When is the best time to get a blood sugar reading after eating? 

Given that we know it takes your body about 90 minutes to clock the sugar in your blood, it’s good to take a blood sugar reading within 60 to 90 minutes of a meal. Testing too soon or too late may give a less-than-accurate picture of what’s going on.

If you’re new to using a CGM, or have recently been diagnosed with prediabetes or diabetes, you may still be getting the hang of what foods work well for you and which ones cause too sharp a spike. Remember: It’s impossible to keep your blood sugar reading at the exact same number at all times, but you do want to avoid large swings in either direction, too low or too high. 

For those with diabetes, your doctor may refer to something called “time in range (TIR),” which is a target blood sugar range for different times of day (e.g., in the morning, after you eat, and before bed).

Post-meal tracking is one way to start understanding the impact food has on your blood sugar levels. This way you can create a personalized approach to choosing foods that are best for keeping your blood sugar levels within the right range for your health goals.

How can I tell which foods will cause my blood sugar to spike?

Until now, you had to adopt a trial-and-error approach — eat a food, wait 60-90 minutes, and then check your blood sugar. If the spike is bad, then you'll want to avoid that food if at all possible and find a healthier alternative. How do you find that healthier alternative that won't spike your blood sugar as much? Repeat the first step, and see what happens.

This is cumbersome and costly (CGMs cost around $80 and last only 14 days, at which point you'll need to buy a new one). Now, however, thanks to AI, the January AI app enables you to see a food's impact on your blood sugar without EVER needing to take a bite — and best of all, the app is totally free to use.

How does it work? The app's proprietary AI is based on thousands of data points. For a detailed look, you can see an in-depth guide on how the predictions are calculated, as well as validated third party research. But what you need to know is that you can easily take a picture of your meal, scan a food's barcode, or search for a food in the 32M-deep database, and you'll see the predicted glucose curve (which is unique to you), as well as healthier alternatives you can compare, so you can make the smartest choice possible — before eating. No more trial and error, no more expensive CGM.

‍Give the free January app a try here.

What should a normal blood sugar level be one hour after eating?

You should always consult with your doctor about what your target blood sugar levels should be, as it’s not always the same for everyone. If you’re looking for a standard benchmark, the American Diabetes Association (ADA) recommends a target of below 180 mg/dL one to two hours after you eat. For people without diabetes, you should aim for a target below 140 mg/dL.

How long after eating should blood sugar return to normal?

“Normal” is going to be different for everyone, so again, you should speak with your health care provider to set targets that are specific to your situation and goals. That said, outside of eating windows, you’ll want to keep your blood sugar levels between 80–130 mg/dL, according to the ADA. For those without diabetes, aim for under 100. You should expect to see your numbers return to pre-meal levels after about two hours. 

Key takeaways

It’s completely normal to see your blood sugar levels rise after you eat, but you don’t want a sharp rise (to over 180 mg/dL). By tracking your blood sugar levels within 60 to 90 minutes of a meal, you can see how your body responds to certain foods and make informed decisions about what foods are the best at stabilizing your blood sugar. After about two hours, your blood sugar should drop back down to its pre-meal level. Keep in mind: these numbers are just average benchmarks. Where you are on your journey — no diabetes, pre-diabetes, or living with diabetes — will determine what your goals should be before, during, and after a meal.