Perimenopause and weight gain: what's hormones, what's habit, and what you can control
Perimenopause is real, and so is its effect on your body. But it's become the buzzword we blame everything on. Anna and Charlotte on what your hormones actually do, the loop that's really driving the weight gain, and the simple things that still work in your 40s.
By Anna & Charlotte · MNU-Certified Nutritionists · Level 3 Personal Trainers
Published 17 March 2026 · Updated 9 June 2026
TL;DR
Perimenopause is the buzzword of the moment, and it's become the thing women in their 40s blame for everything: tiredness, weight gain, lost motivation. Anna and Charlotte's take, after years of coaching women through it: the hormones are real and they do affect your energy, sleep, cravings and where you store fat. But blaming everything on perimenopause is what makes women stop trying. Your metabolism doesn't meaningfully slow until around 60. The real driver of weight gain at this stage is the loop underneath: worse sleep, lower energy, less movement, worse food choices. That loop is yours to change. Strength training two or three times a week, 10,000 steps a day, 30g of protein per meal, decent sleep, and consistency. Not endless cardio, not heavy restriction, not giving up because it's your hormones.
Key takeaways
- Perimenopause is real and hormones genuinely affect energy, sleep, cravings and where you store fat. But it has become a catch-all excuse, and blaming everything on it is what makes women stop trying
- Your metabolism doesn't meaningfully slow until around 60. The weight gain in your 40s is driven more by muscle loss and a tiredness loop (bad sleep, less movement, worse food) than by the hormones themselves
- Muscle is a metabolic organ. The more you have, the more you burn at rest, so strength training two or three times a week is the single highest-value change you can make
- Aim for 10,000 steps a day. Going from a 2,000-step desk-job day to 10,000 lifts your calorie expenditure substantially, without a single gym session
- Most women under-eat protein. Aim for at least 30g per meal. A salmon fillet is only about 20g, so add 200g of Greek yogurt for another 20g. You don't need a protein powder
- Perimenopause is diagnosed on symptoms, not a blood test (which only captures one fluctuating moment). Track your symptoms for a month, print the list, and take it to your GP
- The shift to make: swap yo-yo dieting, heavy restriction and endless cardio for strength, protein, fibre, daily movement and consistency. Match your training to your nutrition and be patient
Is perimenopause really why I can't lose weight?
Partly. But it's become the thing we blame for everything.
Right now, the most common line Anna and Charlotte hear from women in their 40s is some version of: it's my hormones, that's why I can't lose weight. And once you've decided your hormones are the reason, there's a quiet, dangerous next step.
We kind of blame it on that and essentially stop trying. Because, well, it's never going to work anyway, my hormones are defunct, so we give up on even trying.
It's the same move as labelling yourself an emotional eater and using it as permission to binge. The label arrives, and the effort leaves. And here's the part nobody says out loud: twenty years ago, women weren't reaching for this word at all.
20 years ago, women were just not using that term. No one was saying perimenopause. They thought they were mad.
To be clear, that's not a reason to dismiss it. Perimenopause is real, the symptoms are real, and women finally being able to name what's happening to them is genuine progress. The point is narrower: somewhere along the way it went from an explanation to a full stop. This is general education from two coaches who work with women through this stage every day, not medical advice. But everything below is the part that's still in your hands.
Does perimenopause actually cause weight gain?
Yes, the hormones play a role. Anna and Charlotte aren't underplaying that.
Your oestrogen and progesterone fluctuate, rising and falling unpredictably, and that ripples out into the things that govern your weight.
So the weight on your middle isn't imaginary, and it isn't only about willpower. The hormones are real inputs. But they are not the whole equation, and they are not the biggest part of it.
Does your metabolism slow down in your 40s?
This is the myth that does the most damage, so it's worth being precise.
People often think that their metabolism changes over menopause. But it's actually been proven that your metabolism doesn't slow down until over the age of about 60.
If it isn't age, what is it? Two things, and both are within your control.
The first is muscle. As we get older we lose muscle mass and bone density, and muscle is a metabolic organ, it's the tissue that burns through calories. Lose muscle and your metabolism drifts down, not because of a birthday, but because you've lost the engine.
The second is the loop. This is the real culprit, and most women are living inside it without naming it.
That last one is biology, not weakness. When you're short on sleep, leptin and ghrelin (your fullness and hunger hormones) move against you, the same effect seen in shift workers who struggle with their weight. You eat more because your body is telling you to.
You know you should exercise, but you're tired, so you don't. And you know you should eat well, but you're tired, so you can't be bothered to cook proper food, so you end up eating rubbish.
Address the loop, the sleep, the movement, the food structure, and most of the weight gain follows. That's a lifestyle pattern, not a sentence handed down by your ovaries.
How do I keep my metabolism up in perimenopause?
Build muscle. It's the closest thing to a cheat code at this stage.
Anna's favourite way to picture it is a car. A small, efficient engine sips fuel and barely burns anything. A big engine drinks it.
In terms of our body, we want to be the Lamborghini burning through fuel. So the more muscle we have, the quicker we're burning through the fuel.
More muscle means a higher resting burn, a body that handles food better, and crucially, the strength to stay independent and upright as you age. You don't need to live in the gym to get it. You need to lift, progressively, a few times a week. We'll come to exactly how much below.
Why does this matter so much right now?
Because the decisions you make in this decade are really decisions about your seventies.
Your muscle and bone are declining during perimenopause. If you don't act on that now, the version of you in twenty years inherits the consequences.
In 20 years' time, if we don't look after ourselves now, our bodies are going to be frail, possibly with osteoporosis, our muscle mass disintegrated. We're going to be in a much unhealthier position.
The hard part is that the payoff is invisible today. Anna compares it to the marshmallow experiment, where children offered one marshmallow now or a whole packet later almost always grab the one in front of them. Investing in a body you won't feel the benefit of for two decades is genuinely difficult.
So Anna and Charlotte offer a simpler motivator: look one generation up.
Have a look at the generation above you. The people who stayed active, who are now in their 70s still running around in good shape, still exercising, with lots of energy. That is who you want to be. That's not who you become by accident.
You almost certainly know both kinds of seventy-year-old. The difference between them didn't happen at seventy. It happened in the decades like the one you're in now.
Should I see my GP about perimenopause? What about HRT?
Yes, and go in prepared, because how you show up changes the conversation.
The single most useful thing you can do is track. Anna and Charlotte coach their clients to log their symptoms for a month, then print the list and tick off what they've experienced, rather than turning up and saying "I might be perimenopausal, I'm not sure."
Track for a month all the symptoms you've been having, print off a list and tick the ones you've had. That's how you walk into a doctor armed.
One thing worth knowing: don't pin your hopes on a blood test.
Blood tests aren't going to show you much. They show a moment in time. Your oestrogen fluctuates, so you might be caught on a normal day and told you're fine. Perimenopause is symptom-based.
Because it's symptom-led, a phone consultation is a perfectly good place to start. There's nothing to physically examine, it's a conversation about what you're experiencing.
On HRT: Anna started it at 44 and was told by a doctor she was "young to be doing that." Her view is that it's about symptoms, not a number on a chart, and that women shouldn't be talked out of help they need. But that's her personal experience, not a recommendation. HRT is an individual medical decision, and the right move is to have that conversation with your own GP.
So what should I actually do?
Less than you think, done consistently. None of this is complicated.
Two of those are worth expanding, because they're where women lose the most ground.
Protein. It's the nutrient women under-eat the most, and the maths surprises people.
A fillet of salmon only gives you about 20 grams of protein, which isn't plenty. But add 200 grams of Greek yogurt at the end of dinner and that's another 20 grams. Suddenly you've got 40.
You don't need a protein powder to hit your target. Greek yogurt, egg whites stirred into your morning oats, and sensible portions of meat and fish get you most of the way. If you want it mapped out properly, the nutrition guide for women over 40 lays out the aceRULES in full.
Sleep. Perimenopause disturbs it, and broken sleep feeds straight back into the tiredness loop. A proper routine helps more than people expect. Anna's is a hot bath, an acupressure mat, phone plugged in face-down across the room, and a chapter of a book to pull her mind out of the day. And when sleep won't come, she's stopped fighting it.
Instead of lying there going I can't fall asleep, I lean into it. I get up, read a book, then try again an hour later. I never lie there battling it.
What's the one shift to make?
Stop chasing the quick fix. Start building the body.
The old playbook for this stage, yo-yo dieting, heavy restriction, hours of cardio, is exactly what stops working in your 40s. The new one is quieter and far more effective.
That's the whole thing. Perimenopause is real, and it makes this harder. It does not make it impossible, and it is not a reason to stop. The women who come through this stage strong, energetic and in good shape aren't the ones with better hormones. They're the ones who kept showing up.
If you want a coach in your corner who actually understands training and nutrition through perimenopause, that's exactly what aceTRANSFORM is built for.
Frequently asked
Does perimenopause cause weight gain?
Hormones fluctuate during perimenopause and that can shift where you store fat (often to the middle), disturb your sleep, drop your energy and increase cravings, so yes, it plays a part. But the bigger driver of weight gain is usually the knock-on effect: poor sleep leads to less movement and worse food choices, which is a lifestyle loop you can change. The weight gain can be slowed and reversed, it isn't fixed by your hormones.
Does your metabolism slow down in perimenopause?
Not because of your age directly. Research suggests your metabolism stays fairly stable until around 60. What actually slows it is losing muscle mass, because muscle is what burns calories, and moving less because you're tired. Build and keep muscle through strength training, and move more day to day, and you protect your metabolism through this stage.
How do I talk to my GP about perimenopause?
Track your symptoms for about a month and tick them off a list you can print and bring to the appointment. Don't rely on a blood test to confirm it, perimenopause is diagnosed on symptoms and your hormone levels fluctuate day to day, so a single test can easily come back normal. A phone consultation is a perfectly good place to start the conversation. Any decision about HRT is an individual one to discuss with your GP.
What's the best exercise in perimenopause?
Strength training two or three times a week, under an hour each session, progressively getting stronger, plus plenty of walking (aim for 10,000 steps a day). Endless cardio tends to make you hungrier and backfire for weight loss in midlife. Strength training protects the muscle and bone you'll want for the decades ahead, which matters far more at this stage than burning calories in a single session.