How to Tell If You Are Insulin Resistant: The 1-Hour Glucose Test
The Big Idea: Catching And Reversing Insulin Resistance Before Diabetes
If you are looking for the early signs of insulin resistance or how to tell if you are insulin resistant, the standard blood tests often fall short. This new research reveals a powerful marker—the 1-Hour Glucose reading from an OGTT—that catches the problem years before prediabetes or Type 2 Diabetes appears.
This insight builds on our 8-part Metabolic Health Series in the Ikigai blog—an educational foundation covering insulin resistance, glucose dynamics, nutrition, exercise, and metabolic flexibility. Here, we review and translate a new research article through that same lens, helping you connect cutting-edge science with the real-world habits we’ve already introduced.
These insights come from a long-term prospective study that - at time of writing - is being published in Metabolism in the upcoming January 2026 edition. A research team in Germany followed 317 adults through a 9-month lifestyle program and then tracked them for more than a decade. They discovered that a single reading taken 1 hour after drinking a glucose solution during a standard glucose test can uncover early insulin resistance—long before blood sugar levels reach the type 2 diabetes range.
This “1-hour glucose” marker reveals a stage when the body is starting to struggle with insulin control, but the system can still recover quickly with the right lifestyle approach.
In short, it’s a window of opportunity to help restore insulin sensitivity while the body is most responsive to change.
Why the Full OGTT Outperforms Standard Tests for Early Insulin Resistance
At Ikigai, every patient completes a 5-point oral glucose tolerance test (OGTT) with paired insulin levels—our standard way of understanding how your body handles glucose in real time. For readers who may be new to this: an OGTT involves drinking a sweet solution and having blood drawn at several time points (fasting, 30, 60, 90, and 120 minutes). Such detailed testing is not typical in the primary care setting, but the full curve—especially the 60-minute point—reveals early changes in insulin resistance long before traditional tests do.
The study categorized participants based on their metabolic stage::
Normal glucose regulation (NGR): All glucose values in range
High 1-hour glucose: 1-hour ≥155 mg/dL (8.6 mmol/L) while fasting and 2-hour values remained in the normal range. (This is the new early-warning stage.)
IGR (impaired glucose regulation): A later stage on the same insulin-resistance continuum, where glucose control is more disrupted but not yet at the threshold for type 2 diabetes
What They Found: The High 1-Hour Stage is the Turning Point
The 9-month lifestyle program focused on weight loss through individualized nutrition and heart-rate-guided activity. Researchers tracked insulin sensitivity, $\beta$-cell function, liver fat, and visceral fat using MRI, then followed participants for up to 12 years.
1) Early Signs of Insulin Resistance Appear at 60 Minutes
People with a high 1-hour glucose showed early signs of reduced insulin efficiency. Their pancreas was already working harder, producing more insulin to keep blood sugar in range. Crucially, they carried more liver fat and deep belly fat, both contributors to metabolic dysfunction. Their fasting and 2-hour numbers still looked "normal," proving that insulin resistance starts years before typical lab cut-offs.
2) Early Action Completely Reverses the Process
After 9 months of lifestyle change:
Insulin sensitivity and β-cell function in the high 1-hour group returned to normal levels—just like those with fully normal glucose regulation.
Liver fat fell sharply, and deep belly fat declined.
The group further along the continuum (IGR) improved too, but not as completely.
3) The Long-Term Impact on Diabetes Risk
Those in the high 1-hour group were twice as likely to return to full normal glucose control after the program compared with IGR.
Over the next 12 years, their chance of developing type 2 diabetes was about 80% lower than people starting with IGR.
The 60-minute glucose value identified at-risk individuals better than A1C, fasting glucose, or the 2-hour OGTT reading.
Practical Interventions: How to Reverse Insulin Resistance
Type 2 diabetes isn’t a separate disease—it’s the advanced stage of long-term insulin resistance.
Detecting a high 1-hour glucose gives you an early warning while your pancreas and metabolism are still highly adaptable.
This is when lifestyle change works best: before chronic high insulin and fat buildup in the liver make reversal harder.
What the Study’s Intervention Included
The 9-month program in the study focused on three core elements:
Nutrition coaching aimed at ~5% weight loss, emphasizing balanced meals and reduced caloric density.
Heart-rate–guided physical activity, primarily moderate aerobic exercise.
Supportive lifestyle change, with regular follow-up to reinforce habits.
These strategies were enough to reverse early insulin resistance in the high 1-hour group and significantly improve insulin sensitivity, β-cell function, liver fat, and visceral fat.
What We Do at Ikigai
Building on the same principles—but with a more targeted and preventive approach— part of what we incorporate includes:
1. Time-restricted eating (TRE)
Eating within a consistent 8–12 hour window can improve insulin sensitivity and reduce glucose variability.
Earlier, lighter dinners help flatten evening glucose curves.
2. Zone 2 aerobic training
150–225 minutes per week of low-intensity, steady-state movement (walking, cycling, hiking) improves mitochondrial efficiency and glucose disposal.
3. Strength training
2–3 sessions per week build and maintain muscle—the body’s primary glucose-using tissue.
More muscle means better insulin sensitivity and long-term metabolic protection.
4. Being carb-conscious
We focus on quality and timing of carbohydrates:
Limit refined carbs such as white bread, pastries, crackers, chips, white rice, most breakfast cereals, and baked goods.
Avoid simple sugars—especially drinking sugar: soda, sports drinks, sweetened coffees, fruit juice, lemonade, energy drinks. Liquid sugar creates the fastest, highest glucose spikes.
5. Post-meal movement
A 10-minute walk after meals noticeably lowers glucose peaks.
6. Sleep and stress
7–8 hours of high-quality sleep supports insulin and cortisol regulation.
Stress-reduction habits (breathing, outdoor time, short resets through the day) improve metabolic resilience.
The Bottom Line: Don't Wait for Prediabetes
A high 1-hour glucose (≥155 mg/dL) signals early insulin resistance—a reversible stage on the same continuum that leads to type 2 diabetes.
By acting early with strategic nutrition, exercise, and recovery habits, you can restore insulin sensitivity, reduce liver and visceral fat, and dramatically lower your lifetime diabetes risk.
The Ikigai Approach
At Ikigai Health Institute, we measure the full glucose curve (including insulin) to map where you sit on the insulin-resistance spectrum.
Then we build a personal plan—nutrition, movement, recovery, and tracking—to help you move back toward metabolic balance.
Your body has extraordinary capacity to recover when given the right inputs—especially when you act early.
Let us help you take action today.
