Why Did I Get Diabetes?

For many teens and families, hearing the words prediabetes or type 2 diabetes often brings a difficult question: Why me? Why do some people develop blood sugar problems, even when others with similar body sizes or lifestyles don’t?

Thanks to years of scientific research, we now know that the answer isn’t simple. It’s not just about body weight or what someone eats — it’s about how each body responds to food and energy storage. Here’s what the research tells us.

What is Prediabetes and Type 2 Diabetes?

When we eat, our gut breaks down the food into glucose (a sugar found in food and drinks) and releases it into our blood, which is known as our blood sugar level. The body must store this glucose somewhere to use later for energy. If it builds up in the blood, it can be dangerous.

Insulin is an important hormone that is produced in the pancreas, and its role is to lower blood sugar by storing glucose in muscle, liver, and fat tissues. If these tissues can’t listen to insulin’s message to store glucose, known as insulin resistance, glucose builds up in the blood.

In response, the pancreas produces more and more insulin, but this can get tiring. When the pancreas becomes too tired to make enough insulin, blood sugar levels rise because there isn’t enough insulin to store the glucose. This condition is known as prediabetes, and as it gets worse, it becomes type 2 diabetes.

Body Weight is Part of the Story

Over 20 years ago, in one of the first studies of its kind, children and teens with bigger bodies joined researchers to discover that a surprising number of them already had difficulty storing glucose:

• 25% of the children and adolescents had prediabetes
• 4% of the adolescents had full-blown type 2 diabetes

Kids and teens should be in their best health with a strong pancreas, so finding a tired pancreas at an early age can signal a difficult future.

Here’s another key message: not every teen living with a bigger body had prediabetes or type 2 diabetes. In fact, most had normal blood sugar and insulin levels, showing that weight alone does not define your health. There are other factors that contribute to diabetes -- some of which are not in your control, as the next studies found.

You Can Be in a Larger Body and Be Metabolically Healthy

Another study looked closely at teens in bigger bodies and found something powerful: some were insulin sensitive, meaning their bodies were doing a great job keeping blood sugar levels in check.

What made the difference? Two major clues:

• Higher levels of adiponectin, a hormone that tells your body to store fat in safe areas below your skin (known as subcutaneous fat)
• Less fat stored in the liver and muscles, even when their bodies had high amounts of fat overall

This tells us how and where your body stores fat matters as much, or more, than the amount of fat someone has overall. This is what keeps kids healthy, not just a number on a scale. Unfortunately, you can’t simply tell your body where it should store fat. Your body stores fat based on factors like genetics, hormones, and food types – so some of it is in your control, and some of it is not.

Why Some Teens Progress to Diabetes and Others Stay Stable

In a follow-up study, researchers tracked teens with bigger bodies to see whose blood sugar worsened and whose stayed normal. Teens drank a sugary drink, and researchers measured their blood glucose and insulin for three hours. This is known as a glucose tolerance test, and it’s the best way to know how well someone stores glucose.

The researchers found four key reasons why certain teens are more likely to develop prediabetes or type 2 diabetes:

• Teens who already had difficulty storing glucose on the first test
  • Over time, thanks to many teens who took the glucose tolerance test, researchers were able to define three abnormal patterns of glucose and insulin response, years before diabetes developed. Each pattern carried a different risk of developing diabetes, so knowing a teens’ pattern can give early insights into their own risk.
• Teens with the highest body weights within the group
• Teens of African descent, who developed diabetes faster than other teens
• Teens with a variant in the TCF7L2 gene, which is inherited from their family

In other words, the early clues are already there, even before blood sugar crosses into the danger zone. Knowing these clues can mean earlier treatment for people who need it most.

The biggest takeaway? Glucose control in youth with bigger bodies is not one-size-fits-all. Some teens have stable insulin function, while others silently progress toward diabetes. This helps explain why two teens with similar body types and habits may have very different health outcomes.

So…Why You?

Prediabetes and type 2 diabetes are influenced by:

• Where your body stores fat
• How sensitive your tissues are to insulin
• Your unique hormone levels, like adiponectin
• Your genetic background
• Physical activity and food choices

This means that the path to diabetes (or away from it) is deeply individual and can be influenced by factors, some out of your personal control. The good news, when it comes to blood sugar and diabetes, it’s not just why me? It’s also what now?

Early testing, ongoing monitoring, and supportive care can make a powerful difference, no matter your starting point. Moving your body and choosing healthy foods also make a big impact—as researchers saw in the Bright Bodies program. Youth who joined activities like dancing and changed ingredients in their meals had less prediabetes and type 2 diabetes after two years. (For more information, see report ‘Is It Even Worth It?)

Science is giving us more ways to reverse the path to diabetes, all thanks to the many youth who participated in these studies and continue to do so.

This report was written by Abigail Kelley and Clare Flannery, MD

Scientific Studies

Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. Sinha R, Fisch G, Teague B, Tamborlane WV, Banyas B, Allen K, Savoye M, Rieger V, Taksali S, Barbetta G, Sherwin RS, Caprio S. N Engl J Med. 2002 Mar 14;346(11):802-10. doi: 10.1056/NEJMoa012578. PMID: 11893791

The “obese insulin-sensitive” adolescent: importance of adiponectin and lipid partitioning. Weiss R, Taksali SE, Dufour S, Yeckel CW, Papademetris X, Cline G, Tamborlane WV, Dziura J, Shulman GI, Caprio S. J Clin Endocrinol Metab. 2005 Jun;90(6):3731-7. doi: 10.1210/jc.2004-2305. Epub 2005 Mar 29. PMID: 15797955

Predictors of changes in glucose tolerance status in obese youth. Weiss R, Taksali SE, Tamborlane WV, Burgert TS, Savoye M, Caprio S. Diabetes Care. 2005 Apr;28(4):902-9. doi: 10.2337/diacare.28.4.902. PMID: 15793193

Mechanistic insights into the heterogeneity in glucose response classes in youth with obesity: a latent class trajectory approach. Tricò D, McCollum S, Samuels S, Santoro N, Galderisi A, Groop L, Caprio S, Shabanova V. Diabetes Care. 2022 Aug 1;45(8):1841-1851. doi: 10.2337/dc22-0110. PMID: 35766976