It's important to consistently check your blood glucose levels if you have diabetes, especially around mealtimes.
Diabetes affects more than 1 in 10 Americans, yet it can still feel like an unclear and complicated illness to manage. One of the best ways to better understand your diabetes is by regularly checking your blood glucose levels. But what makes your blood glucose levels change? And when is the best time to check it especially around mealtimes? Here we answer those questions and more.
What causes your blood glucose to go up?
Blood glucose (also referred to as blood sugar) refers to the amount of glucose that is circulating through your blood, ideally headed to cells for energy. Insulin is the hormone that allows glucose into our cells, but those with type 1 diabetes don't produce insulin and those with type 2 diabetes are resistant to insulin and don't use it effectively.
Things that can make our blood glucose levels go up include food, stress and illness. Things can can cause our blood glucose levels to go down can include long periods of time without eating, taking too much medication (like insulin) and physical activity.
Each person, regardless of whether they have diabetes, has their own healthy blood sugar target range where their body functions as its best. If you have diabetes, it's important to identify what your range is, and how it compares to a range that would make you feel your best. Talk with your healthcare team about your current range as well as what the healthiest range for you would be.
When is the best time to check your blood glucose after a meal?
Measuring your blood glucose after a meal is important because that is typically when our blood glucose levels are at their highest. Food takes some time to be broken down into usable energy, but most of the food you consume will be digested and raise your blood glucose in one to two hours. To capture the peak level of your blood glucose, it is best to test one to two hours after you start eating.
Post-meal blood glucose monitoring (and record-keeping) is important because it helps you see how your body responds to carbohydrates in general, and also how you respond to particular foods. Managing post-meal blood glucose can help reduce your risk of developing other complications associated with diabetes, such as heart and circulation problems.
After eating, your blood sugar levels begin to rise within 15 to 30 minutes, but only if your meal or snack includes carbohydrates. The speed and level of the increase depend on the type of carbohydrates and other nutrients found in the foods you eat, as well as on your body's ability to manage your blood sugar levels.
The Effect of Carbohydrates
Carbohydrates are the main constituent of food that can raise your blood sugar levels. The amount and the type of carbohydrates you eat influence how quickly your blood sugar levels change after eating. Carbohydrates from liquids, such as juices and soft drinks, are usually digested more rapidly, while carbohydrates from solid foods, such as pasta and fruits, take a bit more time to break down. Foods that don't contain carbohydrates or only very little, such as non-starchy vegetables, butter, eggs, meat, poultry, fish, cheese and nuts, do not have the ability to significantly influence your blood sugar levels.
Glycemic Index and Blood Sugar
Only carbohydrate-containing foods have a glycemic index, which can be used to assess how quickly and how high your blood sugar levels will rise in response to different foods. Many high-glycemic foods can raise your blood sugar levels within as little as 15 minutes after eating, including white and whole-wheat bread, most breakfast cereals, rice, potatoes, french fries, scones and pretzels. Low-glycemic foods have a more modest effect on your blood sugar levels and it may take a bit longer to see a rise. The rise in your blood sugar levels is first seen in your venous blood, the blood drawn at the lab, and it takes a bit longer for the changes in your blood sugar levels to be measured in your capillary blood, the blood used when testing your blood sugars at home.
Fat, Fiber and Mixed Meals
Other foods you eat with carbohydrate-containing foods usually slow down the rise in your blood sugar levels in the post-meal period. For example, fat, fiber and protein all have the ability to delay gastric emptying. If it takes more time for your stomach to churn your food before releasing its content into your intestines where it can be absorbed, the increase in your blood sugar levels can be delayed. For example, even high-glycemic foods won't raise your blood sugar levels as quickly if consumed with butter, extra vegetables and a serving of chicken.
During Blood Sugar Testing
Everybody is different and the speed at which your blood sugar levels rise after eating depends on whether you are healthy, if you have diabetes or insulin resistance or if you exercise after your meal. If you are concerned with your blood sugar levels, ask your doctor for a prescription to get a glucometer to check your own blood sugar levels at home. Measure your blood sugars before eating and every 15 minutes to two hours after a meal to learn how your body responds to different foods.