Before and After: The Effect of Eating on Blood Sugar

What Is Blood Sugar?

Blood sugar, also known as blood glucose, comes from the food you eat. Your body turns some of your food into a sugar that circulates in your bloodstream. Blood sugar can be used for energy immediately. The sugar that isn’t needed to fuel your body gets stored in cells for later use.

Blood sugar is important. But too much sugar in your blood can be harmful. Diabetes is a disease that results from having high levels of blood sugar. Diabetes can lead to problems with your heart, kidneys, eyes, and blood vessels.

The more you know about how eating affects blood sugar, the better you can protect yourself against diabetes. If you already have diabetes, it’s especially important to know the effect of eating on blood sugar.

What Happens When You Eat?

Whether you’re eating an apple, a turkey sandwich, or anything else, your body breaks down and absorbs the food in its various parts. These include carbohydrates, proteins, and fats, along with vitamins and other nutrients.

Most carbohydrates you consume turn into blood sugar. So the more carbohydrates you eat, the higher levels of sugar you will have in your blood. Carbohydrates consumed in liquids are absorbed more quickly than those in solid food. So having a soda will cause a faster rise in your blood sugar levels than eating a slice of pizza.

Fiber is one component of carbohydrates that isn’t converted into sugar, because it can’t be digested and stored by the body. Fiber is important for health, though. Water, vitamins, and minerals don’t contain carbohydrates, so they won’t affect your blood sugar levels.

If you have diabetes, your carbohydrate intake is the most important part of your diet.

High-Carbohydrate Foods

The foods that generate the most blood sugar are those that are high in carbohydrates. These foods include cookies and other sweetened items, as well as healthy items, such as bread, cereal, and fruits.

If you’re watching your carbohydrate intake, you don’t necessarily have to avoid these foods. Instead, you’ll need to be careful about portion size. The more food you eat, the greater the amount of sugar you will absorb.

How often you eat during the day is also important. Try to keep your blood sugar levels pretty consistent. Three meals a day plus a couple of snacks can usually keep your blood sugar fairly steady.

If you have diabetes, your doctor may recommend the amount of carbohydrates you can have during the day. You may also work with a dietitian who is also a certified diabetes educator to plan your meals.

Your overall health, your age, and activity level may all play a part in setting your dietary guidelines.

Exercise and Blood Sugar

Since blood sugar can be used for energy, exercise can have a big effect on your blood sugar levels.

When you use your muscles, your cells absorb sugar from the blood for energy. Depending on the intensity or duration of your exercise, physical activity can help lower your blood sugar for many hours after you stop moving. If you exercise regularly, your body may consistently have lower blood sugar levels.

You’ll have to check your blood sugar levels regularly. This can be done quickly and easily. You may be advised to check after a big meal, before and after exercise, and if you feel sick.

Knowing how certain foods and exercise affect your blood sugar is important in keeping it at a healthy level.

Insulin and Blood Sugar

Insulin is an important hormone that helps regulate your blood sugar levels. The pancreas makes insulin. It helps control your blood sugar levels by signaling cells to absorb sugar from the bloodstream.

If you have type 1 diabetes, your body doesn’t make insulin, so you have to inject insulin every day. You should check your blood sugar levels a few times a day.

If you have type 2 diabetes, your body may produce insulin, but may not use it properly. Your cells may not respond to insulin, so more sugar keeps circulating in the blood. You may not have to check your blood sugar levels every day, but you should follow your doctor’s advice on diet, exercise, and blood sugar monitoring.

When You Eat Too Little

It’s also possible to have consistently low levels of blood sugar. This is called hypoglycemia. Low blood sugar levels can leave you feeling tired, shaky, dizzy, nauseous, confused, and may even cause you to faint.

If you have diabetes, you can also have episodes of hypoglycemia. It may be due to a reaction to your insulin shots, or to a long period in which you didn’t eat properly. If you don’t have diabetes, you can still have hypoglycemia, either as an ongoing problem or as a temporary condition.

Going a long time without eating is unhealthy. This is one of the reasons why it’s important to have breakfast, since your body hasn’t had any food for fuel for several hours.

Watch What You Eat

Carbohydrates aren’t the only things that affect blood sugar. If you consume foods with a lot of fats and proteins, the calories from those foods will be converted into fat in your body. The more weight you gain, the less effective insulin becomes. As a result, your blood sugar levels can rise.

In general, you want to avoid or minimize your intake of sweetened beverages and foods that are high in carbs and fat, and low in healthy nutrients. For example, a couple of brownies have as many carbohydrates as a banana, but the fruit also has potassium and vitamins your body needs. Brownies don’t have those benefits.

If you have diabetes or you’ve been told you have high levels of blood sugar, talk with your doctor or a dietitian about what you can do to eat smarter and healthier.