What is Insulin Resistance? Signs, Causes, and How to Reverse It

The mechanism

Endocrinology textbooks establish a clear sequence. After a carbohydrate-heavy meal, blood sugar rises; the pancreas releases insulin; insulin signals cells to absorb glucose for energy or storage. In a healthy person, a small amount of insulin is enough to clear the meal.

In an insulin-resistant person, the same meal triggers a much larger insulin release because the cells respond sluggishly. Over years of this pattern, two things happen: insulin stays chronically elevated (which biologically blocks fat oxidation), and the pancreas slowly loses capacity to keep up. Dr. Benjamin Bikman, professor of cell biology and physiology at BYU, argues in his research that this chronically elevated insulin, not excess calories, is the root cause of both obesity and most metabolic disease.

We argue this explains a pattern many users report: weight gain that begins gradually, then accelerates, then stops responding to the calorie deficits that worked in their twenties. The math has not changed. The hormonal landscape has.

Common early signs

• Stubborn abdominal weight gain. Insulin preferentially routes excess energy to visceral fat depots.
• Post-meal sleepiness. A steep insulin response triggers a downstream blood-sugar trough that shows up as fatigue 30-90 minutes after eating.
• Carbohydrate cravings 1-2 hours after a meal. The same blood-sugar trough triggers ghrelin (the hunger hormone), creating the familiar "I just ate, why am I hungry?" loop.
• Skin tags and acanthosis nigricans. Dark, velvety patches at the neck or armpits are a classic dermatological sign.
• Elevated fasting glucose or HbA1c. Routine bloodwork showing fasting glucose creeping into the 95-110 mg/dL range, or HbA1c 5.7-6.4%, is the canonical pre-diabetic signal.

We are clear: any one of these alone is not diagnostic. We recommend reviewing patterns with a clinician and asking specifically about a fasting insulin test (often more sensitive than fasting glucose) if multiple signs are present.

How to reverse it

The strategy is mechanical: lower the daily insulin response, and sensitivity returns. Trials have demonstrated that the following levers are most effective:

1. Reduce refined carbohydrates. Bread, pasta, juice, sweetened beverages, and ultra-processed snacks produce the steepest insulin spikes.
2. Anchor every meal with protein and fat. Both slow gastric emptying and flatten the post-meal glucose curve.
3. Add fibre. Vegetables, legumes, and intact whole grains physically slow glucose absorption.
4. Leave 12-16 hours between dinner and breakfast. Dr. Jason Fung pioneered the clinical use of time-restricted eating to reverse type 2 diabetes, establishing that fasting windows are the fastest reliable way to allow insulin to fall low enough for fat oxidation to resume.
5. Move after meals. Even a 10-minute walk has been demonstrated to meaningfully reduce post-meal glucose peaks.

Ready to stop guessing what to eat?

Insulin resistance and PCOS

Polycystic ovary syndrome (PCOS) affects roughly 10% of women and is one of the most common reasons women experience unexplained weight gain despite eating carefully. Research has established that 50-70% of women with PCOS have measurable insulin resistance, often without elevated fasting glucose, meaning standard blood tests will not flag it. The elevated insulin drives the hormonal disruption, elevated androgens, irregular cycles, and persistent abdominal fat, not the other way around.

We argue this makes the insulin-first approach particularly important for women with PCOS. Tracking calories or macros addresses the quantity of food but not the hormonal environment. Targeting a low daily Weight Impact Score, aiming for an average below 4, directly addresses the chronic insulin signal that underlies PCOS-related weight gain. Clinical case series have demonstrated measurable improvements in androgen levels and menstrual regularity in women who significantly lower their dietary insulin load, even without weight loss as the primary target.

How RealFoods helps

The hardest part of reversing insulin resistance is not understanding the levers, it is applying them at every meal, every day. Dr. Mark Hyman, Director of the Cleveland Clinic Center for Functional Medicine, argues that blood sugar regulation through food is the single highest-leverage intervention for people managing insulin resistance or supporting a family member with type 2 diabetes. RealFoods automates that daily judgment: each meal scored 1-10, with a daily target of keeping the average below 5. Lower the daily score, and you lower the daily insulin response by definition.

Continue reading: how blood sugar drives weight gain, foods that secretly trigger fat storage, or the four-step method that works.