Type 5 Diabetes: What It Is And What Makes It Different

You’ve probably already heard of Type 1 diabetes and Type 2 diabetes. More than 38 million Americans have diabetes, and 90% to 95% of those individuals have Type 2. While the two types are notably different, diabetes is essentially a disease in which the body struggles to regulate blood sugar levels.

Unlike Type 1 and Type 2, a Type 5 diabetes diagnosis is new. The International Diabetes Federation officially recognized Type 5 diabetes in 2025, and research estimates that up to 25 million people have it.

So what is this condition that so many people have, and that so many of us don’t know about?

“Type 5 diabetes is a newly recognized form of diabetes that emerges primarily from chronic undernutrition, especially during early life, rather than autoimmune destruction like Type 1 or insulin resistance driven by obesity like Type 2,” said Dr. Ken Berry, a family physician who helps patients with obesity, insulin resistance and Type 2 diabetes.

Dr. Yoon Kook Kim, a board-certified endocrinologist at UM St. Joseph Medical Group, explained how it develops: “It is thought that a long-term, early exposure to undernutrition leads to underdevelopment of the pancreas, which is crucial to insulin delivery and production,” he said. “This leads to a state of inadequate insulin production, which in turn leads to uncontrolled and high blood sugar levels.”

Ahead, these two doctors explain more about how Type 5 diabetes differs from Type 1 and Type 2, as well as other need-to-know information about the condition.

As mentioned, Type 5 diabetes stems from long-term undernutrition, particularly in a person’s formative years. That’s what makes it different from Type 1 and Type 2.

“In Type 1 diabetes, the immune system attacks the pancreatic beta cells, and insulin production collapses,” Berry said. “In Type 2 diabetes, the body becomes resistant to insulin and, over time, the pancreas cannot keep up.”

He added to his explanation of Type 5 diabetes, saying, “Type 5 diabetes, by contrast, involves a defect in insulin production, too, but the trigger is undernutrition impairing the pancreas early on rather than autoimmunity or obesity.”

So all types of diabetes involve a pancreatic issue, but the difference is how it starts.

While the differences are clear, they’re also, well, not — or at least weren’t in the past. “Many people with Type 5 diabetes have historically been misclassified as Type 1 or Type 2, and that misclassification can lead to poor treatment outcomes,” Berry said.

As with many health conditions, and due to the causes and risk factors, some people are more likely than others to have Type 5 diabetes.

“As the condition is largely due to undernutrition during early stages of life, Type 5 diabetes is found more commonly in patients who had chronic significant malnutrition during childhood or adolescence,” Kim said.

“It is most commonly seen in low- and middle-income countries, especially in parts of Asia and Africa,” Berry added. “Because awareness is still emerging, it may also affect marginalized or food-insecure populations in higher-income countries, though this is less well-documented at this time.”

Type 5 diabetes symptoms aren’t much different from the symptoms of Type 1 and Type 2, including increased thirst, frequent urination, elevated blood glucose levels, fatigue and weight loss.

Kim explained that diabetes symptoms are tied to blood sugar levels.

There are distinguishing features between the three types, however. “The individual may be underweight and may have had poor early nutrition,” Berry said. “Because the insulin-secretion defect is the primary issue, rather than insulin resistance, the pattern of disease is different, with less likelihood of ketosis (unlike classic Type 1) despite high blood sugar.”

Ketosis is when your body uses its fat (instead of blood sugar) as fuel and energy. Symptoms include an upset stomach, headache, fatigue, bad breath, insomnia, dehydration, low bone density, high cholesterol and kidney stones.

Some of the signs mentioned above come and go by themselves (aka aren’t necessarily a case of diabetes) or are caused by other factors. So, is seeing a doctor all that crucial? At what point?

The answer: earlier than you might think.

“Anyone experiencing classic diabetes symptoms such as thirst, increased urination, unexplained weight loss or failure to gain weight should see a doctor,” Berry said.

With Type 5 diabetes, he also believed there are extra reasons to act early, such as:

• Having a history of undernutrition or chronic food insecurity, particularly during childhood or adolescence
• Being at a “healthy” or low weight, and showing signs of elevated blood sugar
• Being treated for Type 1 or Type 2 diabetes, and that treatment not working as expected (such as needing very low doses of insulin or not following the usual pattern)

“Misdiagnosis is common,” Berry added. “Early evaluation is key because correct diagnosis helps tailor treatment, and misclassification can lead to overtreatment or undertreatment.”

Kim largely agreed and spoke to certain risk factors. For example, a history of significant and long-term malnutrition at a young age makes a Type 5 diabetes diagnosis more likely.

“Of those patients, if you have been diagnosed with diabetes already, but have had significant challenges in getting better control of the blood sugars despite being on a relatively healthy diet with lower carbohydrate intake and [on] medications typically used for Type 2 diabetes, [you] should consider this,” he continued.

What exactly does treatment entail for Type 5 diabetes? The answer isn’t crystal clear — yet. “Treatment is still evolving because the formal guidelines for Type 5 are in development,” Berry said.

At least currently, it can look similar to Type 1 and Type 2 treatment, though. “As Type 5 diabetes is in some ways closer to early-stage Type 1 diabetes in that there is an underproduction of insulin rather than resistance to insulin, insulin therapy can be quite helpful,” Kim said. “Some medications traditionally used in Type 2 diabetes can also be helpful in helping the lower amounts of insulin ‘work more efficiently.’”

Precautions have to be taken, however, and differences do exist. Right now, Berry said treatment also includes the following:

• Addressing underlying nutritional deficits by improving protein intake, correcting micronutrient deficiencies and supporting overall metabolic health
• Tailoring glucose-lowering therapy carefully — using too much or too little insulin can be dangerous, and the “right” amount will look different for Type 5 cases
• Considering the use of oral medications or other therapies that target beta-cell function rather than just insulin resistance

Treatment is advancing, too, as research continues. Berry has seen diagnostic criteria and treatment protocols for Type 5 specifically, global health efforts to raise awareness and an emerging interest in precision medicine that tailors diabetes support.

Kim felt encouraged about these advancements and also noted that the International Diabetes Federation had launched a new work group for Type 5 diabetes.

“With this increased awareness and studies, we can also hope for more targeted treatment options for Type 5 diabetes in the future,” he said.