Prediabetes, A1C, and Insulin Resistance Explained

 Series: Chronic Conditions & Metabolic Health (Part 2 of 3) 

What elevated blood sugar and A1C mean in everyday terms

Prediabetes with an elevated A1C means your blood sugar is higher than normal most of the time, but not yet in the diabetes range. It signals that your body is becoming insulin-resistant, so insulin is working harder and harder to keep sugars in check. The earlier this is found, the easier it is to reverse.

In simple terms, blood sugar (glucose) is the fuel that runs your body. After you eat, sugar from food moves into your bloodstream. Insulin acts like a key, helping that sugar move into your cells so it can be used for energy.

When cells stop responding well to insulin, your pancreas has to make more and more of it. This stage is called insulin resistance. At first, your blood sugar number may still look “normal,” because the extra insulin is covering the problem. Over time, though, sugar starts to build up in the blood.

Two common lab measures pick this up:

• Fasting blood sugar (usually done after not eating for 8+ hours)
• A1C, which reflects your average blood sugar over about three months

Most adults are told that a fasting sugar of 100–125 mg/dL or an A1C of 5.7–6.4% means prediabetes. The Centers for Disease Control and Prevention (CDC) estimates that more than 2 in 5 U.S. adults have prediabetes, and most do not know it yet.CDC

Why this matters: Slow damage from mildly high sugar can begin years before full type 2 diabetes is diagnosed. Blood vessels, nerves, kidneys, and eyes are especially vulnerable. Addressing insulin resistance early protects all of these systems.

Warning signs of prediabetes and how insulin resistance shows up

Most people with prediabetes feel normal. When symptoms do appear, they are often subtle: extra fatigue, more thirst, sugar cravings, or blurred vision. These are clues that insulin resistance is making it harder for your body to move sugar from the blood into the cells that need it.

Common clues that blood sugar and insulin are out of balance include:

• No symptoms at all – many people only find out from routine lab work.
• Frequent urination and increased thirst – especially at night.
• Unexplained fatigue or brain fog – feeling wiped out after meals.
• Sugar or refined-carb cravings – needing something sweet between meals.
• Blurred vision that comes and goes – especially when sugars swing.
• Tingling or burning in the feet – a sign of early nerve irritation.
• Dark, velvety skin patches on the neck or underarms – called acanthosis nigricans, a classic sign of high insulin.

Insulin resistance also tends to travel with other metabolic warning signs:

• Belly-centered weight gain or a growing waistline
• High blood pressure or borderline-high readings at screenings
• High triglycerides and low HDL (“good”) cholesterol on lab results

From a population standpoint, the risk is large. A major diabetes prevention trial showed that people with prediabetes who did not change their lifestyle converted to type 2 diabetes at roughly 5–10% per year Lancet. That risk climbs if A1C is near 6.3–6.4% or if fasting sugar and A1C are both elevated.

Realistic steps to improve blood sugar and protect long-term health

The same habits that lower blood sugar also ease insulin resistance: modest weight loss, regular movement, better sleep, and cutting back on added sugars and refined starches. Research shows that losing just 5–7% of body weight and walking 150 minutes per week can cut diabetes risk by more than half.

In a large U.S. Diabetes Prevention Program, participants who met those goals lowered their chance of developing type 2 diabetes by about 58% CDC. Newer analyses suggest that 33–59% of adults with prediabetes can return to normal blood sugar within 1–5 years if they sustain healthy changes. Frontiers in Endocrinology

Key levers you can pull:

• Nutrition: Emphasize vegetables, fiber-rich foods (beans, oats, berries), lean proteins, and healthy fats. Shrink portions of white bread, pasta, sweets, and sugary drinks, which cause sharp sugar and insulin spikes.
• Movement: Aim for at least 150 minutes of brisk walking, cycling, or similar activity per week. Even a 10-minute walk after meals can flatten the post-meal sugar rise.
• Weight: For someone who weighs 200 pounds, losing 10–14 pounds (5–7%) can have a meaningful impact on A1C and insulin sensitivity.
• Sleep and stress: Prioritize 7–9 hours of consistent sleep and build in stress management; both poor sleep and chronic stress hormones worsen insulin resistance.

For some individuals—especially those with higher A1C, strong family history, or multiple risk factors—clinicians may add medications such as metformin on top of lifestyle changes. The goal is the same: protect the pancreas, lower insulin levels, and prevent progression.

How this fits with obesity and blood pressure in metabolic health

Elevated blood sugar rarely travels alone. It usually appears alongside excess belly fat, higher blood pressure, and abnormal cholesterol. The shared driver behind this cluster is often insulin resistance, which pushes multiple chronic conditions in the same direction.

In part 1 of this series, we focused on obesity as more than a number on the scale—especially visceral fat around the organs. That same deep belly fat releases inflammatory signals that worsen insulin resistance. As insulin levels climb, they encourage the body to store even more fat, especially around the waist. This creates a feedback loop.

Blood pressure is tied in as well. Insulin can cause the kidneys to retain more salt and water, and it activates systems that tighten blood vessels. Over years, this can lead to hypertension, another “silent” problem that damages arteries, the heart, and the brain.

From a workforce perspective, this cluster of obesity, high blood sugar, and high blood pressure drives a large share of heart attacks, strokes, kidney disease, and high-cost claims. National survey data from 2021–2023 show that nearly 16% of U.S. adults already have diabetes, with prevalence climbing sharply in people with overweight and obesity. CDC NCHS

Seeing these issues as one connected metabolic story—rather than separate problems—helps employees and employers focus on the upstream cause and the most efficient interventions.

When to seek medical care and what tests to ask about

Because prediabetes is often silent, anyone with risk factors—excess weight, family history of diabetes, high blood pressure, or past gestational diabetes—should ask for screening. Simple blood tests can catch insulin resistance and elevated sugar years before serious complications appear.

Important conversations to have with a clinician include:

• Screening tests: Ask about fasting blood sugar, A1C, and, in some cases, an oral glucose tolerance test.
• Blood pressure and cholesterol: These help complete the picture of metabolic health.
• Medication review: Some medicines, such as long-term steroids, can worsen blood sugar control; your clinician can review alternatives if appropriate.

Questions you might bring to an appointment:

• “Do my numbers suggest insulin resistance or prediabetes?”
• “What is my A1C, and what goal range should I aim for?”
• “Would I benefit from meeting with a dietitian or diabetes prevention program?”

Employers can support early detection by offering on-site or near-site screenings, easy access to primary care, and protected time for employees to attend visits. When blood sugar issues are found and treated early, the long-term reduction in emergency visits, hospitalizations, and disability can be substantial.

Practical next steps for employees and employers, plus disclaimer

You do not have to fix blood sugar overnight. Focus on one or two realistic actions—such as replacing sugary drinks with water and walking after dinner—and build from there. Small, steady steps improve insulin resistance and lower long-term risk.

For individuals, useful starting steps include:

• Schedule a primary care visit to review weight, blood pressure, and labs.
• Track one daily habit (steps, sugary drinks, or sleep) for two weeks.
• Choose one change you can sustain, such as packing a higher-protein lunch.

For employers and benefits brokers, practical actions include:

• Embedding biometric screenings and A1C testing into annual wellness campaigns.
• Using onsite, near-site, or shared clinics to provide same-day primary care, coaching, and follow-up for employees with elevated blood sugar.
• Aligning benefits with prevention—covering diabetes prevention programs, nutrition counseling, and digital tools that support behavior change.

When employees can access convenient, relationship-based primary care that understands metabolic health, they are more likely to follow through on testing, lifestyle support, and medication adjustments. That translates into fewer high-cost complications over time.

Educational disclaimer: This article is for general education only and is not a substitute for personal medical advice, diagnosis, or treatment. Individuals should always consult a qualified healthcare professional for questions about their own symptoms, test results, or treatment options.

Series CTA: To see how integrated workplace clinics can help identify and manage obesity, prediabetes, and hypertension earlier—while improving employee experience and controlling plan costs—connect with our team to explore onsite, near-site, and shared clinic models.