Child type 2 diabetes: the fasting insulin test doctors miss

Type 2 diabetes used to be called adult onset diabetes. Today it is showing up in preschoolers, grade schoolers and teenagers, and the numbers are getting worse faster. If you are a parent or grandparent, this is what you need to know about the numbers, the labs that catch it early and the food changes that can reverse it.

The numbers behind the surge

New data from the Colorado Diabetes Registry tracked type 2 diabetes in young people from 2002 to 2023. In 2002, kids aged 10 to 19 had an incidence of 2.37 cases per 100,000. In 2023 it was 22.3 cases per 100,000, almost a tenfold jump.

The trend is also accelerating:

• From 2002 to 2013, incidence rose about 2.9% per year.
• From 2014 to 2023, it rose 4.7% per year.

This matters because a child diagnosed at 4, 7, 10 or 16 has decades more time to damage arteries, capillaries, heart, brain, kidneys and liver than someone diagnosed in their 40s or 50s.

Why a normal blood sugar can fool everyone

Many pediatricians order labs after an overnight fast. In that scenario fasting glucose often looks normal or only slightly high, and the visit ends with "we will check again next year." Meanwhile the child may already have prediabetes or type 2 diabetes.

Hemoglobin A1C is a step in the right direction, but it is a late signal. Before A1C climbs, blood sugar can already be spiking after high carbohydrate, low fat meals. That is why Dr. Berry points to a second test most doctors never consider.

The test most doctors skip: fasting insulin

A fasting serum insulin can reveal hyperinsulinemia years before A1C rises. According to the studies Dr. Berry cites, a fasting insulin above 13 in a child signals a problem. Typical healthy values look like this:

• Young children: around 3.9.
• Prepubertal children older than about 7.5 years: around 5.0.
• Healthy normal weight children at 10.5 to 11 years: about 7.2 in boys and 8.9 in girls.
• Puberty: boys may reach 11 to 13 and girls 12 to 15, but that is the ceiling.

Age and puberty matter when you read the result. He also notes that the same test can flag type 1 diabetes, because those children produce very little insulin, so it is a cheap way to spot a very low level.

Warning signs to act on

You do not have to wait for an A1C above 6.5. Take it seriously if you see any of these:

• A child who is even a little overweight.
• Fasting glucose one or two points above the normal cutoff.
• Dark skin on the neck, under the arms or where the legs rub together.
• An A1C that rose even one tenth of a point.
• A strong family history of type 2 diabetes.
• A diet built on bread, cereal, pasta, chips, sweet drinks, fruit juice and processed snacks.

Current American Diabetes Association guidance recommends risk based screening starting at puberty or around age 10, whichever comes first, for overweight children with additional risk factors. Dr. Berry argues that is too lenient and that a child with even one marker of metabolic syndrome should get an A1C at least once a year, and ideally twice.

How to talk to your pediatrician

Most pediatricians do not treat fasting insulin as a screening test, so go in prepared. Bring printed studies on pediatric insulin ranges, which Dr. Berry links in his show notes. Then state the facts plainly: your child's weight, the glucose reading, the family history and your request for an A1C and a fasting insulin.

What to change at home

If the labs come back abnormal, the plan is to lower carbohydrates gradually and lovingly. This is not a diet and it is not about restricting portions.

1. Remove all added sugar first, including sweetened cereals, soft drinks and sports drinks.
2. Slowly wean off cereal, bread, crackers, chips, cookies and pasta. Grains break down into sugar.
3. Cut back on fruit juice. Even the American Academy of Pediatrics advises whole fruit over unlimited juice.
4. Let your child eat until comfortably full, with three meals and the occasional snack.
5. Offer plenty of protein, animal fat, vitamins and minerals, with more meat, eggs and whole vegetables.
6. Make it a family change and lead by example instead of punishing or nagging.

Never fast a growing child or limit how much they eat. The target is sugar and refined carbohydrates, not calories.

Prediabetes is not a life sentence

If your child already has prediabetes or type 2 diabetes, the same advice applies with more urgency. Damage to small vessels is already happening, but a young body heals fast. Dr. Berry says it can be reversed before it adds up to a heart attack, stroke or kidney failure.

Keep tracking. If A1C goes up by a tenth of a point, treat it as a five alarm fire. If fasting insulin climbs above 15 to 17, treat it as a major red flag. He also notes that official nutrition advice can steer you toward plant forward options, yet many vegetarian staples such as grains and added sugars are exactly what worsen the condition.

Conclusion

A normal fasting glucose does not prove a child is metabolically healthy. Ask for an A1C and a fasting insulin, watch for the early signs, and cut added sugar and refined grains before the damage becomes permanent. Act now, because the child cannot see the problem and the doctor will not find it without the right tests.