Can Hormones Affect My Weight? Let’s Break It Down

For women in their late 30s, 40s & 50s

“Is it just me, or have things changed lately?”

If you’ve found yourself saying this in your late 30s, 40s or 50s—about your energy, your mood, or your body—you’re not alone. Many women notice shifts during perimenopause, the transitional years before menopause. One of the biggest frustrations I hear from women is this:

“I’m doing what I’ve always done, but now I’m gaining weight—and I don’t know why.”

Your body is undergoing some changes. Let’s take a closer look at what’s happening—together.

So… What Are Hormones?

Hormones are chemical messengers your body produces in tiny amounts, but they have BIG effects. Think of them like text messages sent from one part of your body to another, telling it what to do—like when to eat, sleep, ovulate, or burn fat.

They’re made by glands in your endocrine system, including:

• The ovaries (oestrogen, progesterone)

• The thyroid (thyroid hormones)

• The pancreas (insulin)

• The adrenal glands (cortisol)

When your hormones are in balance, you feel like “you.” But when things shift—as they do in perimenopause—your metabolism, mood, sleep, and appetite can all change too.

Can Hormones Affect My Weight?

Yes, they absolutely can—and research backs it up. Here’s how:

1. Oestrogen Drops & Fat Storage Shifts

As oestrogen levels start to decline in your 40s, you may notice fat gathering around your tummy rather than your hips or thighs.

🧠 The science: A 2021 review in Obesity Reviews found that declining oestrogen during perimenopause can alter fat distribution and increase abdominal fat, even without changes in calorie intake or exercise.

👉 Source: Lizcano, F., & Guzmán, G. (2014). International Journal of Endocrinology

2. Insulin Resistance Increases

Insulin helps your cells absorb glucose (sugar) from food. But hormonal shifts can make your body more resistant to insulin—meaning your blood sugar stays higher, and your body stores more fat, especially around your waist.

🧠 The science: A study in The Journal of Clinical Endocrinology & Metabolism showed that perimenopausal women have a greater risk of developing insulin resistance, even without significant lifestyle changes.

👉 Source: Carr, M. C. (2003). JCEM, 88(6)

3. Cortisol and Chronic Stress

Your cortisol levels (aka the “stress hormone”) can increase during perimenopause, particularly with poor sleep and high stress. Chronic cortisol elevation is linked to increased appetite, cravings for high-sugar/high-fat foods, and—you guessed it—abdominal weight gain.

🧠 The science: A 2015 study in Obesity (Silver Spring) linked elevated cortisol levels with greater waist circumference and fat retention.

👉 Source: Epel, E. S., et al. (2000). Obesity Research, 8(1)

4. Thyroid Function Slows Down

Thyroid hormones regulate metabolism. In perimenopause, some women experience thyroid dysfunction (especially hypothyroidism), which can slow metabolism and contribute to fatigue and weight gain.

🧠 The science: Research from Thyroid Research highlights that thyroid dysfunction is more common in perimenopausal women and can lead to increased weight.

👉 Source: Pearce, S. H. S., et al. (2013). Thyroid Research

What You Can Do (And No, It’s Not Just "Eat Less, Move More")

If your body’s been feeling a bit different lately—like it’s just not responding the way it used to—you’re not imagining it. Hormonal changes in your 30s, 40s and 50s can shift the way your body stores fat, handles stress, and even how hungry you feel.

But gold, is we are having more research to support changes you can make to work with your body, not against it.

5 Changes that will make a real difference:

• Add protein to every meal – it helps keep you full, supports muscle, and steadies your blood sugar.

• Get your sleep sorted – aim for 7–9 hours if you can. Hormones love a well-rested body.

• Keep an eye on added sugars – less sugar means better energy and happier insulin levels.

• Find ways to lower stress – even five minutes of deep breathing, a short walk, or journaling can calm that cortisol spike.

Move into weights – strength training is truly key. I know weights can feel really overwhelming and scary for many of us, especially if we have always done cardio for our fitness. But from the age of 40, our muscle strength is on a sharp decline and we really need to fight to maintain muscle.

Final Word

Hormones may be invisible, but their impact is powerful—especially during perimenopause. If your body feels out of sync lately, it’s not about trying harder—it’s about understanding what’s shifted beneath the surface.

You’re not broken. You’re just in a new chapter—and your body is asking for something different.

If you’d like a personalised, evidence-based approach to navigating this stage of life, I’m here to help. As an Accredited Practising Dietitian, I work with women every day to balance hormones, support metabolism, and feel empowered in their bodies again.

Restore - click to find out more about my services

Sources

1. Lizcano, F., & Guzmán, G. (2014). Estrogen deficiency and the origin of obesity during menopause. International Journal of Endocrinology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4027293/

2. Carr, M. C. (2003). The emergence of the metabolic syndrome with menopause. J Clin Endocrinol Metab, 88(6). https://doi.org/10.1210/jc.2003-030310

3. Epel, E. S., et al. (2000). Stress and body shape: Stress-induced cortisol secretion is consistently greater among women with central fat. Obesity Research, 8(1). https://doi.org/10.1038/oby.2000.13

4. Pearce, S. H. S., et al. (2013). Thyroid dysfunction in perimenopausal women. Thyroid Research. https://thyroidresearchjournal.biomedcentral.com/articles/10.1186/1756-6614-6-S1-A30