Why am I gaining weight in my 40s?

If you’ve noticed the scale creeping up in your 40s even though your diet and activity haven’t changed much, you’re not alone. Weight gain during perimenopause is very

common and completely normal. But understanding why it happens can help you take control and feel your best again.

What's happening to your body?

As perimenopause is the transitional period before menopause, your body undergoes hormonal changes where your ovaries will start producing less estrogen and progesterone. These hormonal changes affect your body's systems — including the way you store and metabolize fat.

You might notice the following changes:

• Slow metabolism. Estrogen helps regulate metabolism and where your body stores fat. As estrogen declines, your body tends to hold on to more fat.

• Loss of muscle mass. Starting in your 40s, muscle mass naturally decreases by about 3–8% per decade. Since muscle burns more calories at rest than fat, this loss can make it harder to maintain your weight.

• Insulin resistance. Fluctuating hormones can make your cells less responsive to insulin, leading to blood sugar swings and increased fat storage.

• Sleep & stress. Hot flashes, night sweats, and mood changes can disrupt sleep — and poor sleep increases cortisol, the “stress hormone,” which promotes fat storage and cravings for sugary foods.

What can you do to support your body?

It is more about just counting calories during perimenopause. The type of food you eat, how you manage stress, and how you sleep all play a role in balancing your body.

Here's some things you can try:

• Balance blood sugar: Choose protein and fibre-rich meals to avoid crashes and cravings.

• Prioritize strength training: Building muscle helps boost metabolism and protect bone health.

• Support hormone balance: Aim for whole foods, healthy fats, and plenty of water.

• Manage stress & sleep: Yoga, meditation, or even short walks can help lower cortisol levels.

Reach out for support

If your weight gain feels sudden or unmanageable, or if you’re experiencing other symptoms like fatigue, mood changes, or irregular cycles, it may help to speak with a healthcare provider. Here at METALAB, we can help address all your concerns to help support these imbalances.