What Is Insulin Resistance, and Why Am I Gaining Weight?

Understanding Abdominal Weight Gain in Perimenopause and Menopause

If you’ve noticed your body changing in ways that feel unfamiliar—especially that stubborn belly weight that seems to come out of nowhere during perimenopause or menopause—you’re not alone. 

Many women go through this shift and wonder: Why is all the extra weight going straight to my stomach? 

And maybe more importantly: What’s going on inside my body that’s making this so hard to manage?

A big part of the answer comes down to insulin resistance and how our hormones change as we get older. 

Let’s break it down in a way that makes sense.

What Insulin Resistance Actually Means

Think of insulin as the “key” that unlocks your cells so glucose (sugar from food) can enter and give you energy. When your cells respond well to insulin, your blood sugar stays steady, and your body runs smoothly.

But when you develop insulin resistance, your cells stop “listening” to insulin. It’s like the lock has gotten rusty and doesn’t open easily anymore. 

Your pancreas tries to compensate by making more and more insulin. High insulin levels keep blood sugar somewhat under control, but they also tell your body:

• “Store more fat.”
  
  

• “Don’t let go of fat you already have.”
  
  

And where does most of this fat tend to pile on? Right around your midsection. Research shows that abdominal fat and insulin resistance feed off each other—the more belly fat you have, the more resistant your body becomes to insulin, and the cycle keeps repeating itself (GREM Journal, 2023).

Why Belly Fat Shows Up in Perimenopause and Menopause

Here’s the frustrating truth: even if you’ve stayed at a steady weight for years, perimenopause and menopause can flip a switch in how your body stores fat. A few key reasons:

1. Estrogen shifts where fat gets stored.
   Before menopause, estrogen tends to encourage fat storage in your hips and thighs (think “pear-shaped”). As estrogen drops, that protection goes away, and fat storage shifts to the abdomen. This is why so many women notice their waistline thickening, even if their overall weight hasn’t changed much (Obesity Action Coalition).
   
   

2. Visceral fat is metabolically active.
   Belly fat isn’t just sitting there quietly—it’s active tissue. It releases fatty acids and inflammatory chemicals that interfere with insulin’s job. That makes your body less sensitive to insulin, which keeps insulin levels high, and that high insulin keeps you in fat-storage mode (UH Hospitals, 2023).
   
   

3. Muscle loss means slower metabolism.
   As we age, we naturally lose lean muscle unless we actively work to maintain it. Less muscle means fewer calories burned at rest, and it makes it harder for the body to regulate blood sugar efficiently.
   
   

4. Stress and sleep issues add fuel to the fire.
   Perimenopause and menopause often come with disrupted sleep, night sweats, and higher stress. All of these raise cortisol (the stress hormone), which pushes more fat into the belly area.
   
   

“Why Am I Gaining Weight if I’m Eating the Same?”

This is one of the most common frustrations I hear: “I haven’t changed the way I eat, but suddenly my jeans don’t fit.”

The truth is, your body has changed—even if your habits haven’t. Lower estrogen, rising insulin resistance, and shifts in cortisol all combine to make your metabolism less forgiving. 

That’s why strategies that worked in your 30s (like cutting calories for a few weeks or adding a bit of cardio) often don’t work the same way in your 40s and 50s.

In fact, studies show that women gain an average of 3–5 pounds during the transition to menopause, and up to 20% gain more than 10 pounds—most of it in the abdominal area (Obesity Action Coalition).

Signs Belly Fat Might Be Linked to Insulin Resistance

If you’re carrying more weight around your midsection, especially if it feels firm or “deep” (that’s visceral fat), it may be worth checking in with your doctor about insulin resistance. Other common signs include:

• Sugar or carb cravings that feel hard to control
  
  

• Brain fog, low energy, or afternoon crashes
  
  

• Dark, velvety patches of skin (often on the neck or underarms)
  
  

• Elevated cholesterol or triglycerides
  
  

• A family history of diabetes or PCOS
  
  

What You Can Do About It

Here’s the good news: while you can’t control the drop in estrogen, you can take steps to reduce belly fat and improve insulin sensitivity. Think of these as gentle but powerful lifestyle shifts:

1. Prioritize protein.
   Start your day with protein (eggs, Greek yogurt, protein smoothies). It helps keep blood sugar stable and keeps you full longer.
   
   

2. Strength train regularly.
   Building muscle is one of the best ways to fight insulin resistance. Lifting weights, resistance bands, or bodyweight exercises all count.
   
   

3. Walk daily.
   Movement after meals—even just a 10-minute walk—lowers blood sugar and helps reduce belly fat over time.
   
   

4. Focus on sleep.
   Poor sleep makes insulin resistance worse. Aim for a consistent sleep routine and limit late-night snacking or alcohol, which can disrupt rest.
   
   

5. Watch alcohol and sugar.
   These both raise insulin and promote belly fat storage. Cutting back (even a little) can make a noticeable difference.
   
   

6. Talk to your doctor if needed.
   Sometimes, lifestyle alone isn’t enough. Medications like metformin or hormone replacement therapy (HRT) may be appropriate for some women—always a conversation worth having with a healthcare provider (GREM Journal, 2023).
   
   

Why Belly Fat Matters Beyond Appearance

It’s easy to frame this as just a cosmetic issue—wanting to fit back into your jeans—but belly fat is about more than looks. Visceral fat is linked to:

• Higher risk of type 2 diabetes
  
  

• Cardiovascular disease
  
  

• Fatty liver
  
  

• Increased inflammation in the body
  
  

So, addressing belly fat isn’t about punishment—it’s about protecting your long-term health.

Final Thoughts

If you’ve been feeling discouraged by your changing body, know this: you’re not doing anything wrong. Abdominal weight gain during perimenopause and menopause is incredibly common, and much of it comes down to biology and hormones, not lack of willpower.

But you also have tools available—simple, consistent habits that improve insulin sensitivity and help shift that stubborn belly fat over time. Think protein-rich meals, daily movement, strength training, good sleep, and getting the right support if needed.

You deserve to feel strong, energized, and at home in your body, even through this transition.