When a teen's body starts resisting insulin

In insulin resistance, the pancreas works extra hard to produce more insulin as the body’s cells grow resistant to it, resulting in less glucose being able to enter them to provide energy. (This visual is human-created, AI-aided)

As paediatric endocrinologists, one of the most common concerns we see in the clinic today isn’t diabetes itself, it’s insulin resistance. 

This condition is less known, but plays a central role in the development of type 2 diabetes and other metabolic disorders in teenagers.

With the rise of childhood obesity worldwide, understanding what insulin resistance is and what can be done about it is essential.

And the good news is that the teenage years represent a unique window of opportunity for intervention.

Identifying and managing insulin resistance early can change a child’s health trajectory for the rest of their life.

What is insulin resistance?

Insulin is a hormone made by the pancreas that acts like a key made specially to help glucose (sugar) enter cells to be used for energy.

In insulin resistance, the body’s cells, especially muscle, fat and liver cells, don’t respond normally to insulin.

The hardworking pancreas compensates by producing more insulin, resulting in high circulating insulin levels (called hyperinsulinaemia), to maintain normal blood sugar levels.

Over time, the pancreas becomes overworked and exhausted.

When the pancreas is no longer able to compensate by producing enough insulin to overcome this “resistance”, this leads to higher blood glucose, and eventually, type 2 diabetes. 

In adolescents, insulin resistance exists on a spectrum, from mild to associated metabolic problems.

It is increasingly common, paralleling the global rise in childhood obesity. 

Why does it matter?

During puberty, it’s normal for insulin sensitivity to dip transiently.

This is a physiological change linked to growth and hormonal shifts.

However, in many teenagers at risk, especially those with excess weight or other risk factors, this physiological insulin resistance doesn’t fully resolve.

This increases the risk of:

• Prediabetes and type 2 diabetes
• Dyslipidaemia (abnormal cholesterol and triglycerides)
• High blood pressure
• Non-alcoholic fatty liver disease (NAFLD)
• Polycystic ovary syndrome (PCOS) in girls.

All of these are features of the metabolic syndrome – a cluster of risks that raise long-term cardiovascular (heart) disease risk.

Who is at risk?

Certain factors increase the likelihood that an adolescent will develop insulin resistance. These are:

> Weight and body composition

This is the most significant driver.

Specifically, excess “visceral fat” – the fat stored around the internal organs in the abdomen – is metabolically active.

It releases inflammatory signals that directly interfere with how insulin works.

> The sedentary trap

Muscles are the primary consumers of glucose.

In our digital age, many teens spend hours sitting, thus utilising far less glucose. 

> Dietary patterns

Diets high in ultra-processed foods, refined flours and sugar-sweetened beverages cause frequent, massive spikes in insulin. 

> Genetics and ethnicity

A family history of type 2 diabetes significantly increases risk.

Furthermore, certain ethnic groups including South Asian, Hispanic and African American populations statistically show a higher predisposition to insulin resistance at lower weights.

> Sleep deprivation

Teenagers are notoriously sleep-deprived.

Lack of sleep increases stress hormones like cortisol, which tells the liver to dump more sugar into the blood, further taxing the insulin system.

How do we diagnose?

There is no single diagnostic test, rather, diagnosis relies on clinical clues and suggestive lab tests.

Clinical clues include:

• Acanthosis nigricans – velvety, darkened skin on the neck or armpits
• Rapid weight gain, especially central adiposity
• Family history of type 2 diabetes
• Signs of PCOS in girls
• Hypertension (high blood pressure) or dyslipidaemia.

Laboratory and screening tests may include:

• Fasting glucose and insulin – to calculate an insulin-to-glucose ratio or HOMA-IR index (a research surrogate marker)
• Oral glucose tolerance tests (OGTT) – in high-risk adolescents
• Lipid panel and liver enzymes – to screen for metabolic syndrome and NAFLD.

Insulin resistance rarely exists in isolation.

It’s often part of broader metabolic disturbances, including:

• Prediabetes and type 2 diabetes – chronic insulin resistance eventually leads to inability to maintain normal glucose levels.
• Metabolic syndrome – this is a cluster of high blood pressure, abnormal lipids and central obesity.
• NAFLD – this is rising in frequency among youth.  

What can be done?

Lifestyle interventions are the cornerstone of management and remain the most effective and evidence-supported approach for improving insulin sensitivity in adolescents. 

> Nutrition and eating habits

Encourage a balanced, whole-food approach, rich in vegetables, whole grains, lean protein and fibre.

Reduce sugar-sweetened beverages and processed snacks.

Promote consistent meal patterns rather than frequent grazing.

> Physical activity

Aim for 60 minutes of moderate-to-vigorous activity daily as aerobic exercise improves glucose utilisation.

Include strength training two to three times per week, done in a safe and appropriate manner.

Strength training boosts insulin sensitivity in the muscles.

Even small increases in activity and reduced sedentary time (less screen time) make a measurable difference.  

> Healthy sleep and stress management

Adequate sleep and good sleep quality support metabolic health.

Chronic stress through cortisol and lifestyle patterns can worsen insulin resistance.

Last but not least, family involvement is crucial to success.

Children and adolescents thrive when healthy habits are modelled and positively reinforced at home and school with encouragement and without shame or blame. 

When medications can help

In teenagers with significant metabolic risk, lifestyle changes may not be enough on their own.

The most commonly prescribed medication to improve insulin sensitivity among adolescents is metformin.

It is generally safe, although the dose needs to be gradually adjusted in order to minimise gastrointestinal side effects.

It helps lower glucose levels and can aid in weight stabilisation for some patients.

Metformin is widely endorsed for use in adolescents with impaired glucose tolerance or type 2 diabetes risk.

In select cases and under specialist care, other drugs such as glucagon-like peptide-1 (GLP-1) receptor agonists may be considered, especially where obesity is severe or glucose levels remain high despite metformin and lifestyle changes.  

Medication is never a substitute for lifestyle changes; it is instead a partner in care when needed, tailored to the adolescent’s risk profile and goals.

A message of hope

Insulin resistance in adolescents is increasingly common, but it is not a life sentence.

Early awareness, supportive family environments, smart lifestyle changes and timely medical care can slow, halt, or even reverse the trajectory towards diabetes and heart disease.

As parents and healthcare professionals, our role is to spot the risk early, act together, and empower children and adolescents to build healthy habits that last a lifetime.

Dr Jeanne Wong Sze Lyn is a consultant paediatrician and paediatric endocrinologist. For more information, email starhealth @thestar.com.my. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.