The Sneaky Way Diabetes Affects Metabolism, According to a Dietitian

Ah—the mystical metabolism. With everything you've probably seen online, it may seem like firing up your body's natural calorie-burning machinery will solve all sorts of health problems. After all, your metabolism is responsible for your energy levels. It's also key for basic bodily functions like growing and repairing cells, circulating blood, regulating breathing and body temperature, managing hormones, and maintaining your organs. And, of course, your metabolic speed makes a huge difference in weight management.

And yet, with so much riding on your metabolism, it isn't exactly comforting to know that it relies pretty heavily on blood sugar—which is kind of a big deal if you're living with diabetes. Blood sugar is the way you get energy from the food you eat after it's broken down and absorbed in the body. However, because diabetes means needing to manage your blood sugar due to inconsistent or inadequate insulin response, it could inadvertently affect your metabolism.

So what is a person with diabetes to do? We spoke with Caroline Thomason, RD, CDCES, a northern Virginia-based dietitian and diabetes educator, on the specific process behind why blood sugar and insulin is key for the body's metabolism, and how to best take care of it so you can keep your metabolism running the way it should.

What Is Metabolism and How Does It Work?

Metabolism is actually a chemical process your body goes through when converting the food you eat and the oxygen you take in into energy to fuel all sorts of functions. "Your metabolism responds to your lifestyle input and output—how much food you take in, how much energy you burn to function, the kind of exercise you do, and daily bodily functions," says Thomason.

How fast or slow your metabolism is can be calculated by finding your basal metabolic rate (BMR), which refers to the basic number of calories your body needs for normal day-to-day functioning. While this amount will vary from person to person, it does comprise 60% to 70% of the energy your body requires every day. Another 10% represents the energy it takes to digest the food you eat, while the rest is allotted to your physical activity—not just exercise, but other movements you make throughout the day, like washing dishes or running errands.

How Does Diabetes Affect Your Metabolism?

Calories from food are called energy because they're quite literally used as fuel for the body, thanks to an important process that happens during digestion called glucose metabolism. This is when foods are broken down into simple sugars that turn into glucose, then flow through the blood to provide energy to the body. That blood sugar is then used as a source of energy for the body as it is broken down and absorbed. However, this process can be hampered among those with diabetes.

"In cases of diabetes, blood sugar rises in response to decreased insulin sensitivity (in the case of type 2 diabetes), or a lack of insulin production (type 1 diabetes)," says Thomason.

Glucagon, a hormone that controls your blood sugar levels, and insulin, which is a hormone made by the pancreas to convert sugar into energy, are key parts of glucose metabolism. However, if a person is dealing with irregular levels of insulin, this could mess with the metabolic process.

"Insulin is the 'key' that unlocks the cell door and lets blood sugar inside to be used for fuel," says Thomason. "As a result, insulin is a necessary part of human metabolism and has been shown to be positively associated with good energy levels, blood sugar balance and muscle recovery."

She adds that insulin resistance affects glucose metabolism over time, but doesn't affect your normal BMR. "Your BMR is regulated by your energy intake and output, while insulin helps you to store energy that's coming in but it is not directly influencing metabolism regulation," says Thomason.

Nevertheless, because insulin is vital for how the body's metabolism functions, any alterations to insulin—whether it be reductions or resistance—can also change the metabolism process. This includes stimulating the liver to store glucose for glycogen synthesis, decreasing the concentration of glucose in the blood, and even impacting lipid metabolism, which spurs the production of fatty acids in the liver and even stimulates the accumulation of body fat.

Type 1 Diabetes

"Type 1 diabetes occurs in folks with an autoimmune condition that harms the pancreas's ability to produce insulin," says Thomason. "As a result, blood sugar rises quite quickly after you eat. Insulin in a normal functioning pancreas helps to lower blood sugar, but for people with type 1 diabetes, they are insulin dependent because their blood sugar is so high and they have no way to bring it down. Thus, people with type 1 diabetes are dependent on taking insulin for life."

However, with proper insulin management, Thomason says that those with type 1 diabetes can still maintain normal metabolic function. "People with type 1 diabetes shouldn't worry about a slower metabolism, and instead should focus on lifestyle changes to keep blood sugar in a healthy range."

Type 2 Diabetes

Compared to people with type 1 diabetes, people with type 2 are able to have more control of their diagnosis through lifestyle changes that can affect their blood sugar metabolism.

"For people with type 2 diabetes, diet choices, lack of exercise, increased stress and certain medications will all raise blood sugar and can decrease insulin sensitivity," Thomason says. "As a result, blood sugar metabolism changes drastically in these cases of insulin resistance. Insulin resistance occurs when blood sugar has been elevated for some time and the body stops responding consistently to the insulin that it produces. Some folks may need insulin or other medications to help manage this and improve glucose metabolism."

If a person with type 2 diabetes needs more insulin to manage blood sugar, Thomason explains that, over time, this could correlate with a higher body weight. Thankfully, focusing on a healthier lifestyle can make a difference in your insulin sensitivity.

"It is possible to become more insulin sensitive and reduce the total amount of insulin you take day to day, which can decrease the risk of gaining more weight and keeping a steady metabolism," she says.

How Insulin Can Impact Your Metabolism

"Taking insulin as a medication doesn't inherently change your metabolism, especially with type 1 diabetes, since you need it to live," Thomason explains. "However, if you become more insulin resistant and require additional insulin over time, you may notice that weight gain often accompanies this gradual change."

Nevertheless, while an increased amount of using insulin medication has been correlated with a higher body weight, Thomason says that there isn't proof connecting it directly to decreased metabolism.

"Your body uses insulin to store energy from food and it makes sense that if you're eating more food and requiring more insulin over time, this could lead to a higher body weight," she adds.

Can You Increase Your Metabolism When You Have Diabetes?

The answer, Thomason says, is yes—even if you are living with diabetes. And your diet is a great place to start.

"If you are a person with diabetes, whether it is type 1 or type 2, it may be helpful to focus on a diet rich in high-fiber carbs, enough protein, plenty of fruit and vegetables, and healthy fats," she says. "These foods won't immediately change your metabolism, but they will directly impact blood glucose and insulin responses in the body. You may notice that as your blood sugar is more regulated, you become less insulin resistant and blood glucose metabolism improves. And that could positively impact your weight as you create healthier lifestyle changes—like eating a healthy diet and exercising."

Strength training can be particularly beneficial for increasing one's metabolism. Lifting weights can increase your resting metabolic rate by about 7%, meaning this could increase the number of calories you burn on a daily basis—an average of around 100 more calories burned each day. This is because the body requires more energy to build and maintain muscle mass compared to fat, which increases that metabolic rate.

So no, there isn't one food you can eat that will immediately boost your metabolism, but the eating a balanced, healthy diet and doing regular strength-training exercise can make a difference—even for people who have diabetes.

Bottom Line

Metabolism is the process your body goes through in order to create and use the energy from the calories you consume. This energy is then used to digest food, during daily movement (both exercise and everyday activities), as well as to perform normal bodily functions. This energy comes from blood sugar. However, if your body experiences insulin resistance or a reduction in insulin due to diabetes, this process doesn't work as smoothly. And that's why insulin medication (for type 1) and blood sugar management through healthy lifestyle habits (for type 2) are key for keeping your metabolism humming along.