What A1c range counts as prediabetes?

Prediabetes is an HbA1c of 5.7 to 6.4%. Below 5.7% is considered normal, and 6.5% or above on 2 tests defines type 2 diabetes. Fasting glucose of 100-125 mg/dL points to the same range.

Why test fasting insulin if my glucose is normal?

Because insulin rises years before glucose does. A normal fasting glucose next to a high fasting insulin means your pancreas is working overtime to hold the line, which is the earliest measurable stage of the problem. Fishtown Medicine includes fasting insulin in the standard workup for this reason.

Do I need to cut out carbs completely?

No. Carbohydrate quality matters more than elimination for most people with prediabetes. Whole-food, higher-fiber carbohydrates produce a much smaller insulin response than refined ones, and a CGM trial can show you your own pattern. Rigid bans tend to fail; targets tend to hold.

How fast can A1c come down?

A1c reflects roughly 90 days of average glucose, so meaningful change shows up at the 3-month recheck. Many patients see A1c fall 0.2 to 0.5 points in the first 3-6 months when strength training, protein, and sleep changes hold. Fasting insulin often improves sooner.

Does Fishtown Medicine treat prediabetes or only diabetes?

Fishtown Medicine treats prediabetes as a primary focus, not a footnote. The 5.7 to 6.4 window is where prevention has the most leverage, so the practice runs the full workup, CGM trials, and structured follow-up at this stage, before an endocrinologist would ever get involved.

Why do endocrinologists rarely see prediabetes patients?

Endocrinology practices are built around diagnosed disease: type 1 and type 2 diabetes, thyroid disorders, and hormone conditions. Referral systems and insurance billing both route patients there after diagnosis, not before. Prediabetes sits in primary care's territory, which works well when the practice has time for the workup and the follow-up, and poorly when it has 12 minutes.

Is a CGM accurate enough for someone without diabetes?

Yes, for the pattern-finding job it does at this stage. CGMs read interstitial glucose, which lags blood glucose slightly and can differ by a few points, but the trends, meal responses, and overnight patterns are reliable. For prediabetes the goal is seeing which meals and habits drive your rises, and the devices do that well in a 2-4 week window.

What role does sleep apnea play in prediabetes?

An underrated one. Untreated obstructive sleep apnea worsens insulin resistance through fragmented sleep and repeated oxygen drops, and it is common in the same population that develops prediabetes. When the story includes snoring, morning headaches, or unrefreshing sleep, a sleep study belongs in the workup, because treating apnea can move metabolic numbers that diet changes cannot.

What A1c range counts as prediabetes?

Prediabetes is an HbA1c of 5.7 to 6.4%. Below 5.7% is considered normal, and 6.5% or above on 2 tests defines type 2 diabetes. Fasting glucose of 100-125 mg/dL points to the same range.

Why test fasting insulin if my glucose is normal?

Because insulin rises years before glucose does. A normal fasting glucose next to a high fasting insulin means your pancreas is working overtime to hold the line, which is the earliest measurable stage of the problem. Fishtown Medicine includes fasting insulin in the standard workup for this reason.

Do I need to cut out carbs completely?

No. Carbohydrate quality matters more than elimination for most people with prediabetes. Whole-food, higher-fiber carbohydrates produce a much smaller insulin response than refined ones, and a CGM trial can show you your own pattern. Rigid bans tend to fail; targets tend to hold.

How fast can A1c come down?

A1c reflects roughly 90 days of average glucose, so meaningful change shows up at the 3-month recheck. Many patients see A1c fall 0.2 to 0.5 points in the first 3-6 months when strength training, protein, and sleep changes hold. Fasting insulin often improves sooner.

Does Fishtown Medicine treat prediabetes or only diabetes?

Fishtown Medicine treats prediabetes as a primary focus, not a footnote. The 5.7 to 6.4 window is where prevention has the most leverage, so the practice runs the full workup, CGM trials, and structured follow-up at this stage, before an endocrinologist would ever get involved.

Why do endocrinologists rarely see prediabetes patients?

Endocrinology practices are built around diagnosed disease: type 1 and type 2 diabetes, thyroid disorders, and hormone conditions. Referral systems and insurance billing both route patients there after diagnosis, not before. Prediabetes sits in primary care's territory, which works well when the practice has time for the workup and the follow-up, and poorly when it has 12 minutes.

Is a CGM accurate enough for someone without diabetes?

Yes, for the pattern-finding job it does at this stage. CGMs read interstitial glucose, which lags blood glucose slightly and can differ by a few points, but the trends, meal responses, and overnight patterns are reliable. For prediabetes the goal is seeing which meals and habits drive your rises, and the devices do that well in a 2-4 week window.

What role does sleep apnea play in prediabetes?

An underrated one. Untreated obstructive sleep apnea worsens insulin resistance through fragmented sleep and repeated oxygen drops, and it is common in the same population that develops prediabetes. When the story includes snoring, morning headaches, or unrefreshing sleep, a sleep study belongs in the workup, because treating apnea can move metabolic numbers that diet changes cannot.

Prediabetes Doctor in Philadelphia | The Reversal Window

TL;DR30-second take

Prediabetes (HbA1c 5.7-6.4%) is the stage where type 2 diabetes is still preventable; the Diabetes Prevention Program cut progression by 58% with lifestyle change. Fishtown Medicine measures fasting insulin alongside A1c, uses short CGM windows, and builds a plan around strength training, protein, and sleep, with follow-up at set intervals.

TL;DR: An A1c of 5.7 to 6.4% means your glucose regulation is strained but not broken, and this is the stage where the trajectory can still be turned around. The landmark Diabetes Prevention Program cut progression to type 2 diabetes by 58% with structured lifestyle change. At Fishtown Medicine, the workup goes deeper than A1c, the plan is built around strength training, protein, and sleep, and the follow-up happens on schedule.

The message usually arrives through a patient portal: "A1c 5.9, consistent with prediabetes. Recommend diet and exercise. Recheck in 1 year." It comes with no visit, no plan, and no explanation of what the number means or how much room you have to move it. Then a year passes, the recheck comes back at 6.1, and the same message arrives again.

What I want you to know is that an A1c between 5.7 and 6.4 is not an early version of a life sentence. It is the window where the curve still bends, and the evidence for bending it is some of the strongest in preventive medicine. This page covers what the number means, what a deeper workup adds, and what we do about it at Fishtown Medicine.

What does an A1c of 5.7 to 6.4 mean?

An A1c of 5.7 to 6.4% is the prediabetes range: your average blood sugar over the past 90 days is running higher than optimal but below the 6.5% threshold that defines type 2 diabetes. Roughly 1 in 3 American adults is in this range, and most do not know it, because prediabetes has no symptoms you would notice day to day.

Two facts about this stage matter more than the label:

Progression is not inevitable. In the Diabetes Prevention Program, a large randomized trial, structured lifestyle change cut progression to type 2 diabetes by 58% over 3 years, and it outperformed metformin.
Getting back to normal changes your long-term odds. Follow-up data from that same trial showed that people who returned to normal glucose regulation, even once, had a 56% lower risk of developing diabetes later. Moving the number is not cosmetic; it changes the trajectory.

So when I use the word "reversal," here is what I mean by it: for many people in this window, glucose regulation can return to the normal range and stay there, provided the drivers underneath it get addressed. That is different from a cure, and the tendency toward insulin resistance usually needs ongoing attention. But the window is open, and it is widest right now.

Why does prediabetes start years before your glucose moves?

Prediabetes starts years before your glucose moves because insulin resistance comes first. Your muscle and liver cells respond less and less to insulin, and your pancreas compensates by making more of it. As long as the pancreas keeps up, your fasting glucose and A1c look fine. The Whitehall II study traced this timeline in thousands of adults: insulin sensitivity was falling for roughly 5 years before diagnosis, while fasting glucose stayed deceptively flat until a late, fast climb in the final 3 years.

That timeline is why an A1c of 5.9 deserves more than "recheck in a year." By the time A1c crosses 5.7, the compensation has usually been running for years, which also means there is a measurable stage before it that standard screening skips entirely. We wrote a full explainer on how insulin resistance works if you want the mechanism in plain language.

What does a thorough prediabetes workup add beyond A1c?

A thorough prediabetes workup adds the tests that show how hard your body is working to keep that A1c where it is:

Fasting insulin. The single highest-yield addition. A normal glucose next to a high fasting insulin means the pancreas is compensating heavily, and that combination is invisible to standard screening.
HOMA-IR. A calculation from fasting glucose and insulin that estimates how much insulin resistance is present.
ApoB and a full lipid panel. Metabolic and cardiovascular risk travel together, because insulin resistance changes how the liver packages fats. Advanced lipid testing catches that overlap early.
Liver enzymes with a FIB-4 calculation. Fatty liver disease clusters tightly with prediabetes and is worth catching at this stage.
A comprehensive metabolic panel (CMP), thyroid testing, and waist circumference, which is a more honest measure than BMI.

This is the same panel we run for metabolic health generally, because prediabetes is one window into that larger system.

What moves the number back down?

The interventions that move A1c and fasting insulin are well established, and most of them are things a doctor should coach you through rather than list at you:

Strength training, 2-3 sessions per week, is the floor. Muscle is the largest site of glucose disposal in the body, and building it improves insulin sensitivity more reliably than any other single change. This is the intervention most people in the 5.7 to 6.4 range have not seriously tried.
A protein target, not a diet. Around 1.6 grams per kilogram of ideal body weight daily. Enough protein protects muscle, blunts hunger, and crowds out the refined carbohydrates doing most of the damage.
Walking after meals. Even 10-15 minutes lowers the post-meal glucose rise. Philadelphia makes this easy: the Delaware River Trail, a Penn Treaty Park loop, or simply taking the long way back from lunch.
Sleep of 7-8.5 hours. Short sleep measurably worsens insulin sensitivity within days, and it is the driver I see most often in shift workers and new parents.
Carbohydrate quality over carbohydrate fear. Whole-food carbohydrates with fiber behave differently from refined ones. A Saturday haul from the Palmer Park farmers market beats a rule that bans bread.

Fishtown Medicine

A 90-minute conversation with Dr. Ash. A written plan you can actually follow.

Start your intake

None of this requires perfection. It requires consistency and someone checking the numbers with you.

Where does a CGM fit?

A continuous glucose monitor (CGM) fits best as a short diagnostic trial, typically 2-4 weeks, rather than a permanent accessory. In that window you learn which meals produce your biggest glucose rises, how walking changes them, and what your overnight pattern looks like. For most people with prediabetes, 1 sensor cycle changes eating behavior more durably than months of general advice, because you watch your own data respond to your own choices.

We prescribe CGMs, and over-the-counter options now exist for around $89 per month. Our CGM guide covers the devices, the honest limits of the data, and who benefits most from a trial.

When does medication earn its place?

Medication earns its place when the numbers keep climbing despite a fair trial of the fundamentals, or when the starting risk is high. Metformin has decades of safety data and reduced progression to diabetes by 31% in the Diabetes Prevention Program; it makes sense for people with a higher A1c, a strong family history, or a history of gestational diabetes. GLP-1 medications like semaglutide can be reasonable when significant weight and metabolic dysfunction travel together, though we treat them as tools inside a plan, not the plan itself.

What we do not do is jump straight to a prescription while skipping the workup that shows what is driving your numbers. Medication works best when the training, protein, and sleep foundation is underneath it.

What does prediabetes care look like at Fishtown Medicine?

The first visit runs 60-90 minutes. We pull your records, run the full metabolic panel including fasting insulin, and map where you sit on the insulin resistance timeline. Then we build the plan together: a training floor, a protein target, a sleep plan, and often a 2-4 week CGM trial to make the data personal.

The part that separates this from the portal message you got last year is the follow-up. We recheck labs at roughly 3 months, review them together in an unhurried visit, and adjust. Between visits you text Dr. Ash directly when a question comes up, and messaging is part of the membership. That rhythm is what a membership covers, and it is the reason the plan survives contact with everyday life.

Key Takeaways

An A1c of 5.7 to 6.4% is the window where type 2 diabetes is still preventable, and the Diabetes Prevention Program showed a 58% reduction in progression with lifestyle change.
Insulin resistance starts years before glucose moves, so a fasting insulin level tells you far more than a repeat A1c alone.
Strength training 2-3 times per week, a protein target near 1.6 g/kg, post-meal walks, and 7-8.5 hours of sleep are the interventions that move the numbers.
A 2-4 week CGM trial makes the data personal and changes behavior more durably than general advice.
Medication like metformin earns its place when numbers keep climbing despite the fundamentals; it works best alongside them, not instead of them.

Scientific References

Knowler, W. C., Barrett-Connor, E., Fowler, S. E., et al.; Diabetes Prevention Program Research Group. (2002). Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine, 346(6), 393-403.
Perreault, L., Pan, Q., Mather, K. J., et al. (2012). Effect of regression from prediabetes to normal glucose regulation on long-term reduction in diabetes risk: results from the Diabetes Prevention Program Outcomes Study. The Lancet, 379(9833), 2243-2251.
Tabák, A. G., Jokela, M., Akbaraly, T. N., Brunner, E. J., Kivimäki, M., & Witte, D. R. (2009). Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study. The Lancet, 373(9682), 2215-2221.
Bird, S. R., & Hawley, J. A. (2017). Update on the effects of physical activity on insulin sensitivity in humans. BMJ Open Sport & Exercise Medicine, 2(1), e000143.
American Diabetes Association Professional Practice Committee. (2025). Standards of Care in Diabetes - 2025. Diabetes Care, 48(Supplement 1).

Fishtown Medicine | Services

2418 E York St, Philadelphia, PA 19125(267) 360-7927 hello@fishtownmedicine.comHSA/FSA Eligible

Start your intake

Frequently Asked Questions

Common Questions

For many people, yes, in the sense that glucose regulation can return to the normal range. The Diabetes Prevention Program showed a 58% reduction in progression to type 2 diabetes with structured lifestyle change, and people who returned to normal glucose regulation cut their later diabetes risk roughly in half. The tendency toward insulin resistance needs ongoing attention, but the trajectory is changeable at this stage.

Deep-Dive Questions

Insulin resistance changes how the liver packages and exports fats, raising triglycerides, lowering HDL, and increasing the number of atherogenic particles measured by ApoB. Cardiovascular risk starts climbing in the prediabetes range, before diabetes is ever diagnosed. That is why the Fishtown Medicine workup pairs the glucose picture with advanced lipid testing rather than treating them as separate problems.

Muscle is the body's largest glucose reservoir, and resistance training both builds more of it and makes existing muscle take up glucose more efficiently, partly through pathways that work independently of insulin. Cardio helps too, and the combination is best, but for pure insulin sensitivity per hour invested, building muscle is the stronger lever, and it is the one most patients have never been coached through.

Ready when you are

Start your intake

Dr. Ash reads every intake himself, and answers questions personally - usually within a few hours.

TL;DR30-second take

TL;DR: An A1c of 5.7 to 6.4% means your glucose regulation is strained but not broken, and this is the stage where the trajectory can still be turned around. The landmark Diabetes Prevention Program cut progression to type 2 diabetes by 58% with structured lifestyle change. At Fishtown Medicine, the workup goes deeper than A1c, the plan is built around strength training, protein, and sleep, and the follow-up happens on schedule.

What does an A1c of 5.7 to 6.4 mean?

Two facts about this stage matter more than the label:

Progression is not inevitable. In the Diabetes Prevention Program, a large randomized trial, structured lifestyle change cut progression to type 2 diabetes by 58% over 3 years, and it outperformed metformin.
Getting back to normal changes your long-term odds. Follow-up data from that same trial showed that people who returned to normal glucose regulation, even once, had a 56% lower risk of developing diabetes later. Moving the number is not cosmetic; it changes the trajectory.

Why does prediabetes start years before your glucose moves?

What does a thorough prediabetes workup add beyond A1c?

A thorough prediabetes workup adds the tests that show how hard your body is working to keep that A1c where it is:

Fasting insulin. The single highest-yield addition. A normal glucose next to a high fasting insulin means the pancreas is compensating heavily, and that combination is invisible to standard screening.
HOMA-IR. A calculation from fasting glucose and insulin that estimates how much insulin resistance is present.
ApoB and a full lipid panel. Metabolic and cardiovascular risk travel together, because insulin resistance changes how the liver packages fats. Advanced lipid testing catches that overlap early.
Liver enzymes with a FIB-4 calculation. Fatty liver disease clusters tightly with prediabetes and is worth catching at this stage.
A comprehensive metabolic panel (CMP), thyroid testing, and waist circumference, which is a more honest measure than BMI.

This is the same panel we run for metabolic health generally, because prediabetes is one window into that larger system.

What moves the number back down?

The interventions that move A1c and fasting insulin are well established, and most of them are things a doctor should coach you through rather than list at you:

Strength training, 2-3 sessions per week, is the floor. Muscle is the largest site of glucose disposal in the body, and building it improves insulin sensitivity more reliably than any other single change. This is the intervention most people in the 5.7 to 6.4 range have not seriously tried.
A protein target, not a diet. Around 1.6 grams per kilogram of ideal body weight daily. Enough protein protects muscle, blunts hunger, and crowds out the refined carbohydrates doing most of the damage.
Walking after meals. Even 10-15 minutes lowers the post-meal glucose rise. Philadelphia makes this easy: the Delaware River Trail, a Penn Treaty Park loop, or simply taking the long way back from lunch.
Sleep of 7-8.5 hours. Short sleep measurably worsens insulin sensitivity within days, and it is the driver I see most often in shift workers and new parents.
Carbohydrate quality over carbohydrate fear. Whole-food carbohydrates with fiber behave differently from refined ones. A Saturday haul from the Palmer Park farmers market beats a rule that bans bread.

Fishtown Medicine

A 90-minute conversation with Dr. Ash. A written plan you can actually follow.

Start your intake

None of this requires perfection. It requires consistency and someone checking the numbers with you.

Where does a CGM fit?

We prescribe CGMs, and over-the-counter options now exist for around $89 per month. Our CGM guide covers the devices, the honest limits of the data, and who benefits most from a trial.

When does medication earn its place?

What does prediabetes care look like at Fishtown Medicine?

Key Takeaways

An A1c of 5.7 to 6.4% is the window where type 2 diabetes is still preventable, and the Diabetes Prevention Program showed a 58% reduction in progression with lifestyle change.
Insulin resistance starts years before glucose moves, so a fasting insulin level tells you far more than a repeat A1c alone.
Strength training 2-3 times per week, a protein target near 1.6 g/kg, post-meal walks, and 7-8.5 hours of sleep are the interventions that move the numbers.
A 2-4 week CGM trial makes the data personal and changes behavior more durably than general advice.
Medication like metformin earns its place when numbers keep climbing despite the fundamentals; it works best alongside them, not instead of them.