Insulin Resistance: Symptoms and How to Reverse It
By Dr. John Bartemus, DC, CFMP, Functional Medicine Charlotte, PC. Last updated June 19, 2026.
Short answer: Insulin resistance is when your cells stop responding well to insulin, forcing your pancreas to produce more and more to keep blood sugar in check. It develops quietly, often years before a diabetes diagnosis, and it drives heart disease, weight gain, fatty liver, and cognitive decline. The good news: caught early, it is largely reversible with diet and lifestyle.
Insulin resistance is one of the most important problems in modern health, and one of the most overlooked, because for years it produces no obvious disease label. By the time it shows up as “prediabetes” or “diabetes” on a lab report, it has usually been developing for a long time. Understanding it early gives you the best chance to turn it around.
What insulin resistance is
Here is the chain of events. Carbohydrates and sugars break down into glucose, which your body uses for energy. The pancreas releases insulin to move glucose out of the blood and into muscle, fat, and liver cells for use or storage. When you repeatedly take in more glucose than your cells can handle, the body calls for more and more insulin. Eventually the cells stop responding well; this is insulin resistance. The pancreas keeps compensating until it cannot keep up, at which point glucose floods the bloodstream, damaging nerves and blood vessels, driving inflammation, and setting the stage for chronic disease.
The symptoms most people miss
Insulin resistance has recognizable warning signs, both from blood sugar running too high and too low:
Fatigue after meals, especially carbohydrate-heavy ones
Constant hunger and intense cravings for sweets
Energy crashes and irritability between meals
Waking at 3 or 4 a.m.
Excess abdominal fat
Frequent thirst and urination
Brain fog and difficulty concentrating
Trouble losing weight despite effort
The brain connection is worth emphasizing. Unstable blood sugar is one of the most common drivers of brain fog, because neurons need a steady fuel supply to function.
Why it matters: the diseases it drives
Insulin resistance is a shared root cause behind many conditions that look unrelated on the surface:
Heart disease and high blood pressure
Prediabetes and type 2 diabetes
Non-alcoholic fatty liver disease
Polycystic ovary syndrome (PCOS)
Obesity
Alzheimer’s disease, sometimes called “type 3 diabetes” for its metabolic links
Chronic inflammation and arthritis
It also ties directly to cardiovascular risk. As I explain in my article on cholesterol and heart disease, excess sugar and refined carbohydrates lower HDL, raise triglycerides, and shift LDL toward the small, dense particles that damage arteries. Insulin resistance is often the engine underneath an unhealthy cholesterol panel.
How to reverse insulin resistance
The intervention is simple in principle, though it takes commitment if you have spent years eating the other way. The goal is to give your overworked insulin system a rest and make your cells sensitive to insulin again.
Clear out processed and sugary foods. This includes foods marketed as “healthy” that are still high in sugar, such as many granolas, energy bars, and fruit-sweetened yogurts.
Eat real, whole foods. Build meals around vegetables, quality protein, and healthy fats, with ingredients you recognize.
Choose complex carbohydrates over simple ones. High-fiber foods digest slowly and avoid the glucose surges that drive the problem.
Eat plenty of vegetables. Aim for a wide variety; fiber and plant compounds support healthy blood sugar and gut bacteria.
Exercise, especially strength and intervals. Muscle is a glucose sink. Strength training and high-intensity interval training make muscles more insulin-sensitive.
Protect your sleep. Sleep deprivation promotes inflammation, raises appetite hormones, and worsens blood sugar control.
Manage stress. Stress hormones raise blood sugar, so genuine recovery is part of the metabolic picture.
One more connection worth knowing: blood sugar stability is also central to managing autoimmune conditions like Hashimoto’s thyroiditis, because the spike-and-crash cycle flares inflammation throughout the body.
The bottom line
Insulin resistance is the quiet middle stage between healthy metabolism and chronic disease, and it is the stage where you have the most leverage. If you recognize the symptoms, do not wait for a diabetes diagnosis to act. The sooner you reduce the sugar load and rebuild insulin sensitivity, the easier the road back.
Frequently asked questions
What are the symptoms of insulin resistance?
Fatigue after meals, constant hunger, intense sugar cravings, energy crashes between meals, excess abdominal fat, frequent thirst and urination, brain fog, and difficulty losing weight. Many people have it for years before blood sugar rises enough to be labeled prediabetes or diabetes.
What causes insulin resistance?
A diet high in sugar and refined carbohydrates, excess abdominal fat, physical inactivity, poor sleep, and chronic stress. Over time, cells stop responding to insulin, the pancreas overcompensates, and blood sugar control declines.
Can insulin resistance be reversed?
Yes, especially when caught early. Reducing sugar and refined carbohydrates, eating whole foods, exercising (particularly strength training and intervals), improving sleep, and losing excess abdominal fat can restore insulin sensitivity.
What diseases are linked to insulin resistance?
Type 2 diabetes, heart disease, high blood pressure, non-alcoholic fatty liver disease, PCOS, obesity, Alzheimer’s disease, and chronic inflammation. It is a shared root cause behind many separate-looking conditions.
About the author: Dr. John Bartemus, DC, CFMP, is a functional medicine practitioner, educator, speaker, and Amazon international number one best-selling author specializing in optimizing health through Functional Medicine Charlotte, PC.
This article is for educational purposes only and is not medical advice. If you have diabetes or take blood-sugar medication, work with your clinician before making major dietary changes.
