How Does Type-2 Diabetes Develop?

carbohydrates diabetes glucose inflammation insulin insulin resistance nutrition pancreas proteins weight gain Jan 19, 2024

A table with candy, a glucometer, and the word "diabetes" spelled out

Did you know that 38.4 million Americans have diabetes? That’s almost 12 percent of the U.S. population.¹

And among the people with this chronic condition, just 29.7 million are diagnosed.¹

In 2022, the cost of diagnosed diabetes in the country exceeded 400 billion U.S. dollars.¹

The disease is the main cause of blindness, lower-limb amputations, and kidney failure in adults. Plus, it’s number 8 on the list of the leading causes of death in the United States.²

At least 90 percent of diabetes patients have type-2 diabetes (T2D). Unlike type-1 diabetes, which often progresses quickly, T2D usually develops slowly over time. This means T2D causes invisible changes in the body years before diagnosis.^2,3

But how exactly can you get T2D? To answer this question, we’ll explore the topics below:

Blood sugar and insulin
How insulin resistance happens
Problems in the pancreas
Risk factors for T2D

To start off, let’s see how your body normally controls your blood sugar levels.

Blood sugar and insulin

Your body breaks down food into glucose (blood sugar). The entry of glucose into your bloodstream is a signal for your pancreas to release insulin.⁴

Insulin is a hormone that helps glucose enter your cells for energy use. It also alerts your liver and muscles to store glucose in a form called glycogen.^4,5

Once glucose enters your cells, the levels of sugar in your bloodstream fall. This decrease then signals your blood insulin levels to drop. In turn, lower insulin in your blood triggers your liver to release glycogen and convert it into glucose. This way, your body always has energy even if you haven’t eaten for some time.⁴

You get glucose from carbohydrates and proteins. But these two food types change your blood glucose and insulin levels in different ways.⁶

Carbohydrates can either be simple or complex. Simple carbs, which include sugars and starches, get digested and absorbed into your blood quickly. So, eating simple carbs causes rapid spikes in the levels of glucose and insulin in your blood. By contrast, complex carbs are digested slower. So, they raise your blood glucose and insulin gradually, making for more stable levels of both substances.⁶

If carbs are not available, proteins can provide glucose instead. Proteins get digested through a different process than carbs. This process takes even longer, so it doesn’t cause sudden spikes in your blood glucose levels.^6,7

How insulin resistance happens

Blood sugar control by insulin is a finely tuned process. But when too much sugar regularly enters your bloodstream, the system can get dysfunctional.⁴

A consistently large intake of sugar requires your pancreas to secrete a lot of insulin. Over time though, insulin becomes less effective, and you need more of it to persuade your cells to take up glucose. This condition is called insulin resistance. It’s similar to drug tolerance, which happens when your body adapts to a drug you’ve been using for a long time. You then need higher and higher doses of the drug to produce the same effect.^4,8,9

As insulin resistance progresses, your pancreas tries to compensate by making even more insulin. The problem is, the organ doesn’t have an infinite capacity to produce the hormone. If high sugar intake continues, eventually your pancreas will be unable to keep up, and your blood sugar levels will stay elevated.⁴

At the same time, your blood has a lot of insulin telling your liver and muscles to store glucose. Once these sites are full, your liver sends the excess glucose to fat cells. There, the sugar gets stored as body fat, causing weight gain.⁴

Problems in the pancreas

The beta cells in your pancreas are responsible for insulin production. But as they make a lot of insulin over time, they get exhausted and lose mass.^10,11

Also, chronically high glucose levels promote the buildup of fatty acids in your beta cells. This accumulation prevents the cells from functioning properly.¹²

What’s more, elevated glucose and fatty acids can cause inflammation and oxidative stress in your beta cells and elsewhere. Eventually, these toxic conditions promote the cells’ death.¹¹

In short, the habit of eating or drinking too much sugar impairs your beta cells and kills them in the long run. As a result, your pancreas’ ability to produce insulin becomes impaired.

Together, the above events set the stage for T2D — a chronic disorder marked by persistently high levels of blood sugar due to 1) your cells’ resistance to insulin and 2) insufficient production of insulin by your pancreas.^10,13

Risk factors for T2D

Factors that affect your risk of developing T2D fall into two categories: hereditary and lifestyle factors.¹⁰

Hereditary factors influence just how much sugar consumption is too much, and how quickly it leads to T2D. One of these factors is ethnicity. For instance, compared to other racial groups in the U.S., American Indians and Pacific Islanders are more likely to have T2D. Also, African Americans and Asian Americans have higher rates of the disease compared to whites.^10,14

Another hereditary risk factor is family history. If someone in your family has T2D, then you have a higher chance of developing the condition as well.¹⁰

As for lifestyle risk factors, poor nutrition can induce T2D through various mechanisms. For example, a diet high in simple carbs causes rapid fluctuations in your blood glucose levels. Spikes in blood glucose contribute to the production of reactive oxygen species (ROS) in your blood. In turn, high ROS concentrations increase inflammation, which interferes with your insulin signaling pathways. This interference paves the way for insulin resistance.^10,15,16

On top of that, inflammation itself generates ROS too. This two-way relationship between ROS production and inflammation contributes to the stresses on your pancreatic beta cells, leading to their dysfunction and death.¹⁰

Conclusion

Regularly excessive sugar intake leads to insulin resistance and impairs insulin secretion by your pancreas. These events drive the development of T2D.

Both hereditary and lifestyle factors affect your risk of T2D. Among the lifestyle ones, nutrition plays the biggest role.

T2D can often be prevented through a healthy diet. And contrary to popular belief, this disease is reversible too.

If you’re a type-2 diabetic, there’s one common ingredient you’ll especially want to avoid to reverse your condition. Discover what is by signing up for the Diabetes Diet Solution.

References