In short
Losing weight during perimenopause means working with your changing physiology instead of against it: steadying blood sugar and stress hormones, protecting muscle, prioritising protein and sleep, and fixing the underlying drivers your blood tests can reveal. According to Sarah McLachlan, The Perimenopause Naturopath (BHSc Naturopathy), the "eat less, move more" strategy doesn't just stop working after 40. It often makes things worse.
In this post:
- Why 'eat less, move more' backfires after 40 (including what the SWAN study found)
- The five levers that actually move weight: blood sugar, muscle, cortisol, sleep, and your personal blockers
- Where Ozempic and GLP-1 medications fit
- What a realistic perimenopause weight-loss week looks like
Why the scales won't budge (it isn't lack of willpower)
You're counting calories, doubling down at the gym, maybe even skipping meals, and the scales won't move. Or perversely, they're moving the wrong way.
What the heck is going on? Well, as oestrogen declines in perimenopause, your cells become less responsive to the hormone insulin - they become insulin resistant. So the same food intake is more readily stored around your middle. This is because your blood sugar levels creep up while the cells aren't unlocked to take it up from the bloodstream. Your body thinks it must have more than enough glucose for the cells, so starts storing the glucose as fat. The increased insulin that's produced to try and unlock your cells to glucose also triggers your body to move into fat storage mode.
Cortisol has more influence, so stress and undersleeping push that storage further too, as it increases blood sugar levels and heightens insulin resistance. And muscle, your metabolic engine, starts declining unless you work really hard to defend it. The strategies that worked at 32 assume a body you no longer have.
And it isn't just you: in the landmark SWAN study that followed women through midlife, participants gained an average of 0.7kg per year regardless of age or menopause status, and almost 70% of women report gaining weight across the menopause transition (Hurtado et al., Current Obesity Reports, 2024).
It's not you failing the plan. It's the plan failing you.
The old rules vs what works now
| The old rule | Why it backfires now | What works instead |
|---|---|---|
| Eat less (a lot less) | Under-eating raises stress hormones and burns muscle, slowing your metabolism further | Eat enough, with protein at every meal |
| Move more (harder, longer) | High-intensity everything spikes cortisol, driving storage | Strength training + walking, with real recovery |
| Cut carbs completely | Unsustainable, sleep suffers, rebound is brutal | Smarter carbs, timed around your day |
| Skip breakfast | Blood sugar rollercoaster all day, 3pm cravings | Protein-rich breakfast that holds you 5+ hours |
| Push through on 5 hours sleep | One short night measurably worsens insulin resistance | Treat sleep as a weight-loss tool, not a luxury |
The five levers that actually move weight after 40
1. Fix your blood sugar first
Blood sugar chaos drives hunger, cravings and storage. Protein at every meal (aim for a palm-and-a-half serve), fibre and colour on the plate, and carbs positioned with meals rather than grazed all day. Nothing else works well until this does.
2. Defend your muscle
From our 40s we lose muscle steadily unless we fight for it, and muscle is where you burn fuel. Deakin University's 2026 muscle-mapping research found that many indicators of muscle health in women decline suddenly and sharply around the menopausal transition, rather than gradually the way they do in men (IPAN, Journal of Physiology, 2026). Two or three strength sessions a week beats seven punishing cardio sessions, for body composition and for how you feel.
3. Manage cortisol like it's your job
Stress hormones tell your body to store, especially around the middle. The mental load of midlife is a metabolic factor, not a personal failing. Walks, breath work, boundaries, and actually finishing work at a sane hour are weight-loss strategies.
4. Sleep like it matters (because it does)
Short sleep raises hunger hormones and worsens insulin resistance within days. If you're choosing between a 5am HIIT class and an extra hour of sleep, in perimenopause the sleep usually wins.
5. Find YOUR blockers with real data
This is the step almost everyone skips. Thyroid function, iron status, inflammation, blood sugar markers: when these are off, no generic plan can out-diet them. Standard tests read against "normal" ranges often miss what optimal ranges reveal. We don't guess. We gather data.
"The women who come to me haven't failed at weight loss, because they're not trying hard enough. Almost every one has a findable reason the weight won't shift: insulin resistance, a struggling thyroid, iron so low her cells are running on fumes. When we unearth and address the reason, the body will respond." ~ Sarah McLachlan, The Perimenopause Naturopath (BHSc Naturopathy), Australia
Which lever is your weight stuck on?
Find your starting point
The five levers at a glance
1Blood sugar
3pm cravings or hangry crashes most days?
Start here: protein at every meal, carbs with meals rather than grazed.
2Muscle
Cardio but rarely strength training?
Two or three strength sessions beat seven punishing cardio ones.
3Cortisol
Running on stress and coffee?
Walks, breath work, and boundaries are weight-loss strategies.
4Sleep
Under 7 hours most nights?
One short night measurably worsens insulin resistance.
5Blockers
Never had bloods read against optimal ranges?
Test, don't guess: thyroid, iron, inflammation, blood sugar.
Doing "everything right" and still stuck? Start at lever 5 and work backwards.
Take the free Blockers Quiz and find your first leverWhat about Ozempic and weight-loss medications?
GLP-1 medications are everywhere right now, and for some women they're genuinely useful. But they don't teach you what your body needs for this phase of life, they set you up for significant nutrient deficiencies, and many women worry about what happens when they stop. While some of my clients find GLP-1 medications helpful, they find maximum benefit when they learn what to eat, drink, and do, so perimenopause isn't a sh!t show. Medication or not, the five levers above are what create results that last.
A realistic perimenopause weight-loss week
Three protein-anchored meals a day, no grazing. Two or three strength sessions. A daily walk, ideally after a meal. Alcohol contained to one or two occasions. In bed at a consistent time. That's it. Not sexy, but this is the strategy that fits the body you have now, and it leaves room for dinner out and real life. Strategy beats restriction.
If you're done guessing, there are two ways I can help. If you want the foundations laid out step by step, check out PerimenoGO. And if you want an Eat, Drink, and Do Plan built for your body, based off your blood tests, health history, and phase of life, then book a free Clarity Call. Because weight loss after 40 isn't impossible. You've just been handed the wrong strategy.
Frequently asked questions
Why is it so hard to lose weight during perimenopause?
Because declining oestrogen and progesterone increases insulin resistance, decreases stress resilience and muscle mass, and increases cortisol's strong effect on your fat storage, all at once. The methods that worked in your 30s assume hormonal conditions you no longer have. Different physiology needs a different strategy, not more restriction and effort.
What is the best way to lose weight in perimenopause?
Managing your blood sugar (protein at every meal), strength training to protect muscle, identifying your personal blockers like thyroid or iron issues through proper blood tests and analysis, and genuine self-care and stress management, such as consistent sleep. Together these outperform any calorie-cutting approach after 40.
Can you lose weight in perimenopause without dieting?
Yes, and for most women that's exactly the point. Restrictive dieting raises stress hormones and cuts muscle, which worsens the problem. Sustainable changes to what you eat, drink, and do, built for your body, shift weight without the misery or the rebound.
Should I get blood tests before trying to lose weight?
If you've been trying consistently for months without results, yes. Thyroid function, iron studies, blood sugar markers and inflammation can each stall weight loss, and standard "normal" ranges often miss what optimal ranges reveal. Testing turns guesswork into a plan.
I've tried everything and I still can't lose weight. What am I missing?
Usually it's that you've tried everything other people recommended, and none of it was built for your body in this phase of life. "Everything" tends to mean more restriction, more exercise and more willpower, which are the three things that push a perimenopausal body into holding on to fat. Your body isn't broken and you're not failing the plan. You've been handed the wrong strategy. It's what worked for me too: not more restriction, but personalised nutrition built for this phase of life. That's how I released 19 kilos, and kept it off. Work through the five levers above, and if you'd like to know which one is stuck for you, the Blockers Quiz will tell you in a few minutes.
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