Every woman with PMOS (PCOS) has received the advice. From doctors, from relatives, from strangers with opinions: just eat less. Just move more. Just try harder. And every woman who has actually tried knows the maddening part - you do eat less. You do move more. And the scale responds like you did nothing at all, while a friend on the same routine drops three kilos.

You’re not imagining it, and you’re not failing. The equation genuinely is different in PMOS. The reason has a name: insulin resistance.

The mechanism, in plain language

Insulin is the hormone that moves sugar out of your blood and into your cells for energy. Insulin resistance means your cells have become hard of hearing to that signal - so your pancreas shouts louder, producing more and more insulin to get the same job done. Research suggests this affects a majority of women with PMOS - lean women included - with estimates commonly landing between 35 and 80 percent depending on how it’s measured.

Here’s why that wrecks the “calories in, calories out” story. Insulin isn’t just a blood sugar hormone - it’s a storage hormone. When it runs chronically high:

Your body is biased toward storing energy as fat, particularly around the middle, and is reluctant to release it - even in a calorie deficit.
Hunger and cravings get louder. High insulin can drive blood sugar dips that trigger genuine, physiological hunger - especially for quick carbohydrates. That afternoon craving isn’t weakness; it’s chemistry.
Energy drops. When cells struggle to take up fuel, fatigue follows - which makes the “just move more” advice land on a body already running on a drained battery.
The loop feeds itself. High insulin nudges the ovaries to produce more androgens, androgens worsen insulin resistance, and weight gained makes both worse. It’s a cycle, not a character flaw.

“You were never bad at weight loss. You were playing on a harder difficulty setting nobody told you about.”

Why this context matters right now

This mechanism is exactly why the current conversation around PMOS and weight - from lifestyle-first approaches to the new generation of GLP-1 medicines - is really a conversation about insulin. Different paths approach the same underlying problem differently, and which one makes sense for you depends on how much insulin resistance you actually have, your phenotype, your fertility plans, and your circumstances.

This article won’t tell you which path to take - that’s a decision for you and a doctor who knows your case. What it will tell you is this: any weight conversation in PMOS that hasn’t measured your insulin resistance is a conversation happening in the dark.

The test that tells the truth: a fasting glucose alone misses roughly 40% of glucose disorders in women with this condition. An oral glucose tolerance test (OGTT) - ideally with insulin measured alongside - is how insulin resistance actually gets seen.

Letting go of the shame

Perhaps the most damaging thing about “just eat less” is what it implies: that your body works like everyone else’s, so your results must reflect your effort. Years of that message teaches women to distrust themselves - to believe they’re lazy or lying to themselves about what they eat. The biology says otherwise. Once insulin resistance is measured, named, and factored in, the story changes from “I keep failing” to “my body has a specific, well-documented mechanism that needs a specific, informed approach.”

That reframe isn’t just kinder. It’s more accurate - and it leads to better decisions, whichever treatment path you and your doctor eventually choose.