Why Am I Eating Less But Gaining Weight After 40?
← Back to Learn · By Kathryn Carter · Last updated: 16 August 2026
If you've found yourself eating less than you did in your 20s, yet the scales keep creeping up, you're not imagining it.
It's one of the most common frustrations women experience during perimenopause and menopause.
You skip breakfast, eat healthy meals, say no to dessert, yet your jeans feel tighter every month.
So what's actually going on?
The answer has much less to do with willpower than you might think.
The biggest myth about weight gain after 40
For years we've been told weight loss is simple:
Eat less. Move more.
While creating a calorie deficit is still important, it ignores what changes inside a woman's body after 40.
During perimenopause and menopause, hormonal changes can affect:
- Where your body stores fat
- How much muscle you maintain
- Hunger and fullness signals
- Energy levels
- Sleep quality
- Stress hormones
All of these influence how easily your body gains, or loses, weight.
You're probably losing muscle without realising it
From our 30s onwards, women naturally begin to lose muscle mass, a process that speeds up during menopause.
Why does this matter?
Muscle burns more energy than fat, even while you're resting.
As muscle declines, your body simply doesn't need as many calories as it once did.
That means the amount of food that maintained your weight at 35 may now cause weight gain at 45.
This is one reason strength training and adequate protein become so important.
Hormonal changes encourage fat storage
As oestrogen declines, your body often changes where it stores fat.
Many women notice weight shifting away from their hips and thighs and towards their abdomen.
This is why so many women say:
"I woke up one day and suddenly had a belly."
It's rarely because they suddenly started eating more.
It's because their body is responding differently to the same habits.
Poor sleep makes weight loss harder
If you're waking at 3am, struggling with night sweats or simply sleeping less, your body is already working against you.
Poor sleep can:
- Increase hunger hormones
- Reduce feelings of fullness
- Increase cravings for sugary foods
- Make it harder to resist snacking
- Leave you too tired to exercise
This creates a cycle that's incredibly common during menopause. Our guide to menopause and sleep explains what helps.
Eating less isn't always the answer
Many women respond by cutting food even further.
Ironically, this can make things worse.
Eating too little often means missing out on:
- Protein to maintain muscle
- Fibre to control hunger
- Vitamins and minerals
- Energy needed to stay active
Instead of focusing on eating less, it can be more effective to focus on eating smarter.
The two nutrients many women are missing
Protein
Protein helps maintain lean muscle while you're losing weight.
It also keeps you feeling fuller for longer, making it easier to avoid unnecessary snacking.
Many experts now recommend aiming for around 25-30g protein per meal for women in midlife. Here's how to work out your own number.
Fibre
The average Australian woman consumes far less fibre than recommended — the adequate intake is 25g a day.
Fibre helps:
- Slow digestion
- Keep you feeling fuller
- Support healthy blood sugar levels
- Feed beneficial gut bacteria
- Support digestive health
A meal that is high in both protein and fibre is far more satisfying than one that's high in refined carbohydrates alone. More on fibre for women over 40.
Why meal replacements can help after 40
When they're designed properly, a meal replacement isn't about starving yourself.
It's about making one meal each day nutritionally balanced and portion controlled.
The best for women over 40 should provide:
- High protein
- High fibre
- Vitamins and minerals
- Low added sugar
- Ingredients that keep you satisfied for hours
Consistency is often far more important than perfection.
Replacing one meal each day with a balanced shake can remove the guesswork while helping you stay in a calorie deficit without constantly feeling hungry. Our guide to choosing a meal replacement shake covers what to compare.
How MyPause Slim Down Shake is different
Unlike a standard protein shake, MyPause Slim Down Shake was developed specifically for women experiencing hormonal weight gain.
Each 56g serve provides:
- 30.4g plant protein to help maintain lean muscle
- 6.9g fibre to support fullness and digestive health
- Approximately 25% of the daily value across 16 vitamins and minerals
- 2.9g sugars
- No artificial colours, flavours or cheap fillers
- Gluten, dairy and soy free
- Packed in Australia from imported ingredients
Replace one meal a day for steady weight loss, or two meals a day for faster results, alongside a balanced diet.
Formulated meal replacement. Use as part of a kilojoule-controlled diet and regular physical activity.
The bottom line
If you're eating less but still gaining weight after 40, you're not failing.
Your body has changed.
The good news is that the solution isn't extreme dieting.
It's understanding what your body needs now:
- More protein
- More fibre
- More strength training
- Better sleep where possible
- A sustainable approach you can stick with
Small, consistent changes are far more powerful than another restrictive diet.
If you want to learn more, keep reading here.
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