One of the most frustrating things about prediabetes is that it rarely announces itself clearly. There’s no dramatic symptom that sends you to the doctor. No pain, no obvious dysfunction—just a slow, quiet accumulation of metabolic changes that most people don’t recognize as warning signs until years down the line when they get a blood test and hear a number they weren’t expecting. The early signs of prediabetes are real and recognizable in retrospect, but they’re easy to rationalize away: of course I’m tired—I’ve been busy. Of course I’m craving sugar—I didn’t sleep well. Of course I’m gaining weight—I’m getting older.
The reason those rationalizations feel convincing is that they’re not entirely wrong. Fatigue, sugar cravings, and weight gain do have many causes. But when they appear together—particularly alongside abdominal weight gain that doesn’t respond to usual efforts, a family history of type 2 diabetes, or a history of hormonal conditions like PCOS—they take on different significance. The difference between recognizing these early signs and waiting until blood glucose is clearly diabetic is the difference between prevention and management.
At SustainMD, Dr. Allison Barbee, MD, is board-certified in both internal medicine and obesity medicine. Her clinical practice includes routine metabolic evaluation that goes beyond standard glucose testing to identify insulin resistance and prediabetes early—when they’re most responsive to treatment. SustainMD serves patients across North Carolina, California, Florida, and Maine through telehealth, which means specialist-level metabolic evaluation is accessible without needing a referral to an endocrinologist or waiting months for a specialist appointment.
Why Prediabetes Goes Unrecognized So Often
Part of why prediabetes slips by is the way standard screening is done. Most primary care labs include a fasting blood glucose test as part of a basic metabolic panel, and this test doesn’t detect the early insulin resistance phase. Fasting glucose can remain normal for years while insulin levels are significantly elevated—the pancreas working overtime to compensate. By the time fasting glucose rises into the prediabetic range, the underlying insulin resistance has typically been present for a significant amount of time.
More sensitive markers—fasting insulin, HOMA-IR, a two-hour glucose tolerance test—can identify metabolic dysfunction earlier, but they’re not part of routine screening in most primary care settings. The result is that many people with significant insulin resistance receive no metabolic intervention until their fasting glucose is elevated enough to meet prediabetes criteria, at which point the condition is already more entrenched.
SustainMD’s comprehensive metabolic evaluation includes these more sensitive markers, enabling earlier detection and intervention. Learn more about the approach on the Insulin Resistance Boot Camp page.
Early Warning Signs of Prediabetes
Persistent Fatigue That Doesn’t Match Your Activity Level
When cells can’t efficiently use glucose for energy—because insulin resistance is impairing glucose uptake—the result is a kind of metabolic inefficiency that shows up as fatigue. You’re producing energy less effectively than you should be, even if you’re sleeping and eating enough. This isn’t the normal tiredness that follows a busy week. It’s a persistent low-grade exhaustion that’s there when you wake up and doesn’t fully resolve with rest.
The energy crashes that often follow high-carbohydrate meals are another variant of this pattern. A large glycemic load causes a rapid rise in blood glucose followed by an overcorrected insulin response, which then drops glucose too quickly—producing an energy crash an hour or two after eating. Over time, this cycle erodes consistent energy throughout the day.
Intense and Persistent Sugar or Carbohydrate Cravings
This is one of the most consistently reported experiences among patients with insulin resistance and prediabetes, and it makes physiological sense. When insulin resistance is present and cells aren’t efficiently using glucose, the brain perceives this as an energy deficit and signals for more glucose—driving cravings for fast carbohydrates and sugar. The more of these foods you eat, the more the cycle perpetuates. This isn’t a behavioral problem; it’s a hormonal feedback loop.
- Cravings that are strongest in the afternoon or after meals are particularly characteristic of blood sugar dysregulation. The post-lunch energy dip many people experience—and attempt to solve with sugar or caffeine—can be an early marker of insulin and glucose instability.
- Difficulty stopping eating sweet or starchy foods, or feeling like you need something sweet after every meal, may reflect the brain’s response to impaired glucose utilization. Addressing the underlying insulin resistance often reduces these cravings significantly—not through willpower but by correcting the hormonal signals driving them.
Unexplained Weight Gain, Particularly Around the Abdomen
Abdominal weight gain that doesn’t correlate with a clear change in eating or activity habits is a significant early warning sign. When insulin levels are chronically elevated due to insulin resistance, insulin promotes fat storage—and the abdomen, which has a high density of insulin receptors and cortisol receptors, is where fat tends to accumulate most prominently. This visceral fat then becomes its own driver of further insulin resistance and inflammation.
The frustrating pattern many patients describe is trying to eat well and exercise without seeing the abdominal fat respond. This is metabolically consistent with insulin resistance—the standard weight loss equation doesn’t work as efficiently when insulin is chronically elevated, because the body’s fat-burning pathways are suppressed.
Brain Fog and Difficulty Concentrating
The brain is highly glucose-dependent, and blood sugar instability—the kind that accompanies insulin resistance—can produce real cognitive effects. Difficulty concentrating, short-term memory lapses, mental slowness, and what many patients describe as ‘brain fog’ are commonly reported alongside other metabolic symptoms. These symptoms often worsen after high-carbohydrate meals and improve somewhat after protein-rich meals, which reflects the brain’s sensitivity to blood sugar fluctuations.
Skin Changes: Acanthosis Nigricans and Skin Tags
Acanthosis nigricans is a distinctive skin change associated with insulin resistance: darkened, velvety-textured patches that develop in skin folds—typically the back of the neck, armpits, and groin. The appearance reflects the effect of high insulin levels on skin cells. It’s not a cosmetic issue; it’s a clinical sign of underlying insulin resistance that dermatologists and physicians both recognize.
Skin tags—small, flesh-colored growths that appear in similar skin fold areas—are also associated with insulin resistance and elevated insulin levels. Multiple skin tags appearing in middle age, particularly when other symptoms are present, are worth mentioning to your physician as part of a metabolic screening conversation.
For patients with PCOS—a condition frequently associated with insulin resistance and skin changes—SustainMD’s evaluation addresses the hormonal and metabolic connections between these conditions. More information is available on the PCOS conditions page.
Increased Thirst and Frequent Urination
These are classic symptoms of more advanced blood sugar elevation, but they can begin to appear in prediabetes—particularly if blood glucose is trending toward the higher end of the prediabetic range. When blood glucose is elevated, the kidneys work to excrete the excess glucose, drawing water with it and producing increased urination. The resulting fluid loss creates genuine thirst. If you’ve noticed these symptoms becoming more prominent, a blood sugar evaluation is warranted.
What to Do If You Recognize These Signs
Recognizing these signs doesn’t mean diabetes is inevitable or even imminent. Prediabetes and insulin resistance are among the most modifiable metabolic conditions—meaningful intervention at this stage consistently delays or prevents progression to type 2 diabetes and reduces the downstream cardiovascular and metabolic risks. But meaningful intervention requires accurate evaluation, which means more than a standard fasting glucose test.
A comprehensive metabolic evaluation should include fasting glucose and insulin, HOMA-IR, hemoglobin A1C, a fasting lipid panel (including triglycerides, which are often elevated in insulin resistance), and when appropriate, hormonal markers. This provides a complete picture of where you are on the metabolic spectrum and what interventions are most likely to be effective.
If you’re experiencing several of these warning signs, SustainMD’s telehealth-based evaluation makes metabolic screening and treatment planning accessible from home. See what the evaluation process looks like through the insulin resistance treatment program.
Frequently Asked Questions
1. Can prediabetes be reversed?
Yes, in many cases. Prediabetes is one of the most modifiable stages of metabolic disease. With appropriate intervention—targeted nutrition changes, regular physical activity, weight reduction if applicable, improved sleep, and medication when indicated—many patients return to normal blood glucose ranges and avoid progression to type 2 diabetes.
2. What are the first signs of prediabetes?
The most common early signs include persistent fatigue, strong sugar and carbohydrate cravings, unexplained abdominal weight gain, difficulty concentrating, afternoon energy crashes, and in some cases skin changes like acanthosis nigricans. Standard blood tests may show normal fasting glucose even when these symptoms are present.
3. How is prediabetes diagnosed?
Prediabetes is typically diagnosed through fasting blood glucose between 100 and 125 mg/dL, hemoglobin A1C between 5.7 and 6.4 percent, or a two-hour glucose tolerance test result between 140 and 199 mg/dL. Fasting insulin and HOMA-IR can identify underlying insulin resistance before these thresholds are reached.
4. Does prediabetes always become diabetes?
No. Research estimates that 70 to 80 percent of people with prediabetes will develop type 2 diabetes without intervention, but intervention—including lifestyle change, weight loss, and medications—significantly reduces this risk. The earlier treatment is initiated, the greater the likelihood of preventing progression.
5. Can I have prediabetes with a normal fasting glucose?
Yes. Insulin resistance can be significant while fasting glucose remains in the normal range, because the pancreas compensates with higher insulin output. If you have symptoms consistent with insulin resistance, asking for fasting insulin and HOMA-IR testing may reveal metabolic dysfunction that standard glucose testing misses.
6. What foods should I avoid with prediabetes?
Foods that cause rapid blood glucose spikes are most problematic: refined grains, added sugars, sugar-sweetened beverages, and highly processed snack foods. A personalized nutrition plan that accounts for your metabolic markers and food preferences is more effective than a generic exclusion list.
7. How quickly can prediabetes progress to diabetes?
The progression rate varies significantly between individuals. Some people remain in the prediabetes range for years; others progress more quickly, particularly if underlying risk factors are not addressed. Active metabolic management can significantly slow or halt this progression at any stage.
8. Is fatigue a sign of prediabetes?
Persistent fatigue can be one of the earlier signs of insulin resistance and prediabetes, particularly when it’s accompanied by energy crashes after meals, strong carbohydrate cravings, and difficulty concentrating. Fatigue has many causes, so it’s most meaningful when it appears alongside other metabolic warning signs.
9. What is a normal A1C level versus prediabetes?
A normal A1C is below 5.7 percent. Prediabetes is defined as an A1C between 5.7 and 6.4 percent. An A1C of 6.5 percent or higher on two separate tests meets the diagnostic threshold for type 2 diabetes. A1C doesn’t capture short-term blood sugar fluctuations, so additional testing may be warranted when symptoms suggest metabolic dysfunction.
10. Can a telehealth doctor evaluate me for prediabetes?
Yes. SustainMD provides comprehensive metabolic evaluations via telehealth for patients in North Carolina, California, Florida, and Maine. Lab work is ordered through your local lab, and the evaluation and consultation with Dr. Barbee take place virtually. You don’t need an in-person visit to get meaningful metabolic screening and treatment planning.
Disclaimer
This content is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making decisions about your health. Treatment recommendations vary based on individual circumstances, medical history, and clinical evaluation.
