Prediabetes

Condition: Prediabetes  |  Category: Metabolic Health  |  Reviewed by: Brian Lamkin, DO

What Is Prediabetes?

Prediabetes is defined conventionally as a fasting glucose between 100 and 125 mg/dL, a 2-hour glucose tolerance test result between 140 and 199 mg/dL, or an HbA1c between 5.7 and 6.4 percent. Approximately 96 million American adults, nearly 1 in 3, meet these criteria, and the vast majority are unaware of their status. Without intervention, up to 70 percent of individuals with prediabetes will develop type 2 diabetes within their lifetime.

From a functional medicine perspective, the prediabetes label captures only a late-stage snapshot of a metabolic continuum that begins with insulin resistance years to decades earlier. By the time fasting glucose rises into the prediabetic range, the compensatory hyperinsulinemia that sustained normal glucose is beginning to fail, beta cell reserve is declining, and significant vascular, inflammatory, and metabolic damage has already accumulated.

The critical clinical opportunity is not at the prediabetes threshold but in the 5 to 15 years before it, when fasting insulin is elevated and HOMA-IR is rising while glucose remains entirely normal. Prediabetes is not the beginning of the problem. It is the late middle of a process that started much earlier.

Why It Matters

Common Symptoms

Root Causes: A Functional Medicine Perspective

Prediabetes does not develop in isolation. It is the convergence of multiple modifiable upstream disruptions that have been operating for years before glucose becomes abnormal.

Progressive Insulin Resistance and Beta Cell Decline

As peripheral tissues become less responsive to insulin, pancreatic beta cells compensate by producing greater amounts of insulin to maintain glucose in the normal range. This compensatory hyperinsulinemia sustains normal glucose for years while beta cell demand accumulates. Eventually, beta cell reserve begins to decline under the chronic demand burden, and fasting glucose rises into the prediabetic range. By this point, some beta cell loss has already occurred. The goal of functional intervention is to reduce insulin demand before this point is reached.

Visceral Adiposity and Systemic Inflammation

Visceral fat releases inflammatory cytokines including TNF-alpha and IL-6 that directly impair insulin receptor signaling throughout the body. This inflammatory insulin resistance accelerates beta cell stress through glucotoxicity and lipotoxicity. Visceral fat reduction is not a cosmetic outcome in prediabetes management; it is the primary mechanism through which a significant proportion of prediabetes reversal occurs.

Sleep Deprivation, Gut Dysbiosis, and HPA Dysfunction

Even modest sleep restriction of one to two hours per night produces measurable insulin resistance in clinical studies. Gut dysbiosis with reduction of Akkermansia muciniphila and butyrate-producing species impairs intestinal glucose regulation and drives systemic inflammatory insulin resistance through LPS translocation. Cortisol elevation from HPA axis dysfunction promotes hepatic gluconeogenesis and suppresses peripheral insulin signaling, elevating fasting glucose independent of dietary intake.

Conventional vs Functional Medicine Approach

Key Labs to Evaluate

A complete prediabetes evaluation requires markers that characterize the upstream insulin resistance, not just the downstream glucose.

How to Interpret These Labs Together

Common Patterns Seen in Patients

• The patient who was told to watch their diet and come back in a year: HbA1c of 6.1 percent, told to reduce carbohydrates; returns 12 months later with HbA1c of 6.4 percent; the generic dietary advice did not address the fasting insulin of 19 uIU/mL, the sleep deprivation, the gut dysbiosis, or the cortisol pattern that are driving the progression
• The normal-glucose patient with significant insulin resistance: fasting glucose of 94 mg/dL and HbA1c of 5.5 percent; technically not prediabetic; fasting insulin of 24 uIU/mL and HOMA-IR of 5.6; visceral fat accumulating, triglycerides rising; the metabolic trajectory will produce a prediabetes diagnosis within 3 to 5 years without intervention that is available and effective right now
• The motivated patient who reversed prediabetes: HbA1c of 6.2 percent at baseline; 12-month comprehensive intervention including low-glycemic nutrition, resistance training, sleep optimization, and berberine; HbA1c of 5.3 percent and fasting insulin of 5.2 uIU/mL at follow-up; this is achievable and should be the explicit treatment goal in every prediabetic patient
• The stress-driven prediabetic professional: eating well, exercising, but sleeping 5 to 6 hours per night and under sustained occupational stress; cortisol-driven hepatic gluconeogenesis and sleep-induced insulin resistance are the primary mechanisms; dietary modification alone produces inadequate improvement because the cortisol and sleep axes are not addressed

Treatment and Optimization Strategy

The Reversal Protocol

Prediabetes reversal is defined as sustained HbA1c below 5.7 percent and fasting glucose below 100 mg/dL without glucose-lowering medication. This is achievable in a substantial proportion of motivated patients with comprehensive root-cause intervention that addresses dietary pattern, exercise type, sleep quality, stress physiology, and gut health simultaneously. The Diabetes Prevention Program demonstrated 58 percent reduction in progression with structured lifestyle alone. Adding targeted nutraceuticals, metabolic optimization, and root-cause resolution produces superior outcomes.

What Most Doctors Miss

• Fasting insulin is not measured in prediabetes evaluation: the most actionable early marker of insulin resistance and the primary driver of glucose elevation in prediabetes is absent from the standard prediabetes workup; without it, the degree of insulin resistance is invisible and treatment cannot be properly targeted
• Prediabetes reversal is not presented as an achievable goal: the majority of prediabetic patients are told to watch their diet and return annually; the evidence that structured intervention reverses prediabetes in a majority of motivated patients is not communicated as a realistic, explicit treatment goal
• The intervention window closes gradually as beta cell reserve declines: every year of untreated prediabetes involves some degree of beta cell stress from chronic hyperinsulinemia; the earlier the intervention, the more beta cell reserve remains to support recovery; watchful waiting is not neutral, it is progressive
• Cardiovascular and cognitive damage begin in the prediabetic range: many clinicians communicate prediabetes as a warning of future risk without recognizing that the inflammatory, endothelial, and neurological consequences are already accumulating in the prediabetic metabolic environment

When to Seek Medical Care

Any finding of fasting glucose above 100 mg/dL, HbA1c above 5.6 percent, or triglycerides above 150 mg/dL warrants a comprehensive metabolic evaluation including fasting insulin and HOMA-IR rather than annual monitoring alone. This is the intervention window, not a reason to wait.

Seek urgent evaluation for symptoms suggesting acute hyperglycemia including excessive thirst, frequent urination, or significant unintentional weight loss, as these may indicate more advanced glucose dysregulation than prediabetes criteria reflect.

Recommended Testing

Frequently Asked Questions

How The Lamkin Clinic Approaches Prediabetes

At The Lamkin Clinic, prediabetes evaluation begins with fasting insulin, HOMA-IR, and adiponectin alongside standard markers. We assess visceral fat burden, sleep quality, cortisol pattern, gut microbiome health, and inflammatory load as the specific upstream drivers. Treatment is built around reversal as the explicit goal, with measurable milestones at 3, 6, and 12 months.

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Related Symptoms