Does Weight Affect Egg Quality? What Fat Folks Need to Know
This post is sponsored by Rejoova. Formulated by three fertility experts, Rejoova have supplements designed to support egg quality, sperm quality, and mitochondrial function. Use code FERTILE for 10% off at getrejoova.com. Please note they currently ship to the US and Canada only. AD: I earn a small commission if you use this link, at no extra cost to you.
If you’re navigating fertility as a fat person, you've likely been told your weight is affecting your egg quality. Maybe those words were said directly. Maybe they were implied. Maybe nobody ran a single test and yet somehow your body size had already explained everything.
That moment stays with you. I know, because I hear about it constantly from the folks I work with. And I want to address it directly, because the evidence does not support what you were told.
What the research shows about weight and egg quality
There is no established biological mechanism that directly links body fat to poor egg quality. Let me say that again, because it tends to take a moment to land: there is no clear direct pathway from fat tissue to damaged eggs.
Research into chromosomal abnormalities, one of the key markers of egg quality used in IVF, has found no significant difference across BMI ranges. Fat folks are not producing more chromosomally abnormal eggs than thin folks simply by virtue of being fat.
What there is, in some studies, is a correlation. But correlation is not causation, and this distinction matters enormously when the conclusion being drawn is that you need to lose weight before anyone will treat you. The research does not support that conclusion. It never did.
What really affects egg quality
In episode 37 of Fat and Fertile, I spoke with Marc Sklar, an integrative fertility specialist with over 25 years of clinical experience supporting couples all over the world. I asked him what the research shows about egg quality. Here is what he said.
Stress. Sleep. Blood sugar stability. Mitochondrial health.
None of those things require you to change your body size.
Stress is at the top of the list. Chronic stress causes inflammation in the body, disrupts hormone regulation, and affects how well your hypothalamus and pituitary gland communicate with each other. Over time, that disruption can lead to thyroid issues, irregular ovulation, and changes in egg quality. And it does not matter whether that stress is emotional, physical, or dietary. The body responds to all of it.
Sleep comes next. Not sleep as a nice-to-have, but quality sleep as a biological necessity. Poor sleep leads to inflammation. Inflammation affects reproductive function. A consistent, good night's sleep is one of the most powerful things you can do for your fertility, and it does not require a prescription.
Blood sugar stability matters more than most people realise. When blood sugar spikes and crashes throughout the day, that dysregulation drives inflammation and disrupts hormones. Three balanced meals a day with good protein and fat at each one is what Marc recommends: not caloric restriction, not extended fasting, actual nourishment spread across the day.
The extra layer: what weight stigma does to your body
This is the part of the conversation that does not happen often enough.
We know that weight stigma causes chronic stress. We know that experiences of weight bias increase inflammation in the body. We know that weight cycling, the pattern of losing and regaining weight through repeated dieting, also increases inflammation.
This is what is happening for many fat folks navigating fertility. They are carrying the biological effects of weight stigma. They are carrying the inflammation from years of yo-yo dieting they were told was necessary. They are walking into appointments already braced for dismissal, which is its own form of chronic stress.
And then they are being told that their body is the problem.
The system has created many of the conditions it then blames on the body. That is not a small thing to sit with.
Why restrictive dieting makes things worse
This matters particularly because so many fat folks are told to restrict their eating before they can access fertility care. Very low calorie diets, extended fasting, cutting out entire food groups. Marc is direct on this: these approaches deplete the nutrients your cells need to function. They create physical stress on the body. They dysregulate blood sugar.
They work against your fertility. Not for it.
If you have been restricting, and you have been struggling, please know that is not a failure of willpower. Restrictive diets fail people. And in the context of fertility, they are actively working against the goal.
Mitochondrial health and what you can do about it
The mitochondria are the energy source of every cell. As we age, mitochondrial function naturally declines, which is one reason egg quality gets more attention as people get older. But research shows that mitochondrial function can be supported. The foundations that matter most are the same ones Marc named: stress management, quality sleep, nourishing food, movement that feels good rather than punishing.
“Supplements can also play a role, but only once those foundations are in place. Marc co-founded Rejoova specifically to address mitochondrial health for egg and sperm quality.
If you want to explore them, use code FERTILE for 10% off at getrejoova.com. ”
Please note Rejoova currently ship to the US and Canada only.
AD: I earn a commission if you purchase through this link, at no extra cost to you.
What you can do right now
Focus on the things you can control. Not your weight. Your body actively defends its weight. The research on long term weight loss is consistent: it does not work for the vast majority of people. That is not a willpower problem. That is biology.
What Marc kept coming back to, and what I come back to in my own work, is this: what does your body need from you right now? Not to perform health for a fertility clinic. Not to earn the right to treatment.
But, what would help you feel better in your body day to day?
For most people that looks something like: enough sleep, food that sustains you across the day rather than restricts you, ways to give your nervous system a break, movement that feels good rather than punishing. Not a checklist. Not a programme.
Just the question: what does my body need, and can I give it a little more of that today than yesterday?
These things matter for egg quality. They also matter for you. You do not have to be trying to conceive to deserve them.
You deserve care now
If you found this post because someone told you your weight is affecting your egg quality, I want you to take a breath.
You do not have to fix your body before you deserve support. The research does not back up what you were told. There are real, practical things you can do right now, in the body you have, that will make a difference.
You deserve to make decisions from a place of possibility. Not fear.
If you want someone in your corner to help you work out what is actually going on and what your next steps are, my Fat Positive Fertility Roadmap session is the place to start. Ninety minutes, just us, building a strategy that fits your situation.
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Resources:
Find Marc Sklar: marcsklar.com and reproductivewellness.com
Rejoova supplements (code FERTILE, 10% off, US and Canada only): getrejoova.com — AD: affiliate link
Get the book: Fat and Fertile
Full episode transcript available on request.