The fear that lifting weights will make women bulky is the single most damaging idea in women’s fitness. Not because it’s the most obviously wrong — there are wronger ideas in the field. But because it’s the most consequential. The women who avoid the weights room because they’re worried about getting bulky lose access to the training that protects their bone density, sharpens their brain, reduces their risk of falls in later life, and makes the difference between independence and frailty in their seventies and eighties. The cultural anxiety about visible muscle costs women, in the long run, their health.
Dr Stacy Sims, the New Zealand-based exercise physiologist and nutrition scientist, has been making this case for two decades. The biology is unambiguous and has been for as long as anyone has bothered to study it. Women, on conventional training programmes and conventional diets, do not get bulky. They get strong. They get leaner. They get more capable. They protect a body that, after forty, will otherwise start losing the things that make day-to-day life possible.
In an extended interview with Unfiltered,part of our wider Sims interview series, Sims set out the science underpinning the case for women lifting heavy, the cultural reasons the bulky myth refuses to die, and the practical case for power-based training in particular for women approaching the menopause.
The myth that weight training makes women bulky won’t go away. How much does this fallacy frustrate you?
If you go into a gym right now, you’ll see that it’s very gendered. Walk in as a woman and ask about a gym membership and they’ll ask how much weight you want to lose, point you at the cardio equipment, mention the spin classes and the yoga classes. Walk in as a man and they’ll ask what you want to lift, show you the racks, talk about the strength components. It’s automatically gendered.
So that’s one of the big barriers. Women want to take better care of their health, but they’re being ushered into bootcamp classes and cardio. And when we’re looking at what it actually means to get into the gym and lift heavy and do power-based training, there’s still that misnomer that it’s masculine, that it’s going to masculinise a woman. It’s not.
The honest answer to the original anxiety is this: women do better with power-based training than men do, in some respects. The neural recruitment patterns, the central nervous system response, the muscle fibre profile — women respond to heavy lifting really well. But responding well doesn’t mean getting bulky. It means getting strong. The two aren’t the same thing. The shorter way to put it is one Joe Warner offered in our conversation: if lifting weights made you bulky, then surely all the men in the gym would be ripped. Walk into any commercial gym and you’ll see they’re not. If it’s that hard for men to get bulky, with their hormonal advantage, it’s going to be considerably harder for women.
What does it actually take to get bulky?
This is the part most women never hear. To build the kind of bulk people fear from lifting, you have to do three things, and you have to do all three at once.
You have to eat in abundance. We can’t build tissue if we don’t have extra calories. The protein component matters enormously and the timing of that protein matters too. You’re talking about a sustained calorie surplus, not the small surplus most active women run.
You have to lift, and lift, and lift, with sufficient volume and intensity to drive hypertrophy as the primary adaptation. That means a programme structured around hypertrophy, not general strength.
And you have to avoid cardio. Almost completely. As soon as you start doing any kind of high-intensity work — sprint intervals, conditioning circuits, even sustained moderate cardio — the metabolic and hormonal environment shifts away from hypertrophy and the bulk doesn’t accumulate.
So the look that women fear — the physique-competitor or bodybuilding look — is the result of years of disciplined, abundant eating, deliberately programmed high-volume lifting, and zero cardio. That’s not a side effect of “lifting weights.” It’s a project. Look at someone like Annie Thorisdottir at the CrossFit Games. She’s powerful, she’s muscular, she works extremely hard at maintaining the bulk she has, because that bulk is a function of what she does as an athlete. It does not happen by accident.
Are women starting to get this? Or is it still a battle?
It’s a generational thing — or maybe an age thing rather than a generational one. Women in their mid-thirties and below are really embracing it. That’s the offshoot of the cultural shift a few years ago around “strong is the new skinny.” We started seeing women in fitness magazines pictured with actual barbells, not the two-kilo dumbbells that used to be the default. Social media played its part, with athleisure brands and lifting communities normalising what it looks like for women to be strong.
For women in their late thirties and older, the cultural baggage is harder to shift. There’s still the hangover of the 1980s and the supermodel era — the spin classes, the Pilates, the yoga, the imperative to be small. When you start saying “power-based training” to that demographic, people freak out. That doesn’t fit with what they think being healthy looks like.
Which is the wrong way round, because that’s the demographic that needs power-based training most. The younger women who’ve already embraced it have decades to build on. The older women who are scared of it are running out of time.
Why does this matter so much for women in their 30s and 40s?
This is where the conversation needs to move beyond aesthetics entirely. When women in their thirties and forties ask why they should lift heavy, the honest answer isn’t about how they’ll look in three months. It’s about what they want to be doing when they’re eighty.
Resistance training is the bedrock of healthy aging for women. Bone density is the most obvious case — women lose bone density rapidly through perimenopause and into post-menopause, and resistance training is one of the very few interventions that meaningfully protects it. A woman who’s been lifting heavy through her forties and fifties is materially less likely to break a hip in her seventies. That sentence sounds clinical until you spend time with the data on what happens to women after a hip fracture, which is grim.
But it goes further than bone. Resistance training builds new neural pathways. The case for aerobic exercise and brain health is well-established — increasing BDNF, increasing brain tissue volume, all of that. The case for resistance training is different and arguably more important. The way the central nervous system has to learn to recruit muscle fibres under heavy load creates the neural adaptations associated with reduced risk of Parkinson’s, Alzheimer’s and dementia. The brain ages better in women who lift.
Then there’s proprioception — the body’s sense of where it is in space and time. That sense degrades with age, and it’s one of the main reasons older people fall. Resistance training preserves it. So you get the dual benefit: a woman who lifts is less likely to fall in the first place because her proprioception is better, and if she does fall she’s less likely to break something because her bone density is higher and her muscle is protective.
So when I tell women who are older that resistance training matters, I’m not really talking about the training block they’re doing right now. I’m not talking about how much they’ll be able to deadlift in six weeks. I’m talking about what they want to do when they’re eighty. They want to be independent. They want to be walking. They don’t want joint replacement. They don’t want to be living in frailty. Resistance training is the bedrock of all of that.
Why have you put plyometrics at the centre of your menopause training programme?
Plyometrics is the next layer. Resistance training maintains muscle mass and strength. Plyometrics maintains muscle quality and power — and power is the first thing to go.
We see this in the data clearly. Women losing strength is one thing; women losing power is faster and more consequential. Power is what catches you when you stumble. Power is what gets you up off the floor. Power is what lets you cross a busy road without hesitation when you’re seventy-five. The decline in power outpaces the decline in strength, and only specific kinds of training maintain it.
Plyometric work — explosive rebound work, fast neural recruitment of muscle fibre — is the training stimulus that addresses this directly. It’s central nervous system work as much as it is muscle work. It’s also creating an acute metabolic stress that the body responds to in useful ways. Plyometrics produces a really sharp blood glucose response and improves blood glucose uptake without relying on insulin. That matters enormously for women in late perimenopause and early post-menopause, when insulin resistance starts to creep up. Plyometric training is one of the few interventions that addresses this.
The pushback I get is always the same: I can’t jump, my knees won’t let me. Which is a fair concern but not the end of the conversation. You don’t need to box-jump thirty inches. You can do low-depth box jumps. You can do counter-movement jumps. You can do battle ropes if you don’t want to leave the floor. The training principle is power-based explosive work, not the height of the jump. Most women can find a version of plyometric training that works for them. And if joint integrity is genuinely the issue — which it sometimes is, given the rise in inflammation and osteoarthritis around perimenopause — then we strengthen everything around the joint first, the way we’d build up to heavy lifting from a deload, and then progress.
How does a busy woman fit this in?
Honestly, more easily than she thinks. The training prescription for a perimenopausal woman doesn’t require an hour in the gym five days a week. It can be short and sharp.
A typical session might be thirty-five to forty minutes. A couple of compound movements in the three-to-five rep range, finished with a few thirty-second sprint efforts as hard as you can with a minute of recovery between each. That gives you the heavy load and the central nervous system stimulus from the lifting, plus the metabolic stress and power output from the sprints. Three sessions a week of that is a real training programme.
If thirty-five minutes still feels like too much, take a twenty-minute block and just lift. I do this myself. I’m sitting here in my jeans and a t-shirt because I did exactly that before dinner. My daughter had soccer practice for twenty minutes. I missed getting to a proper gym, so I did heavy bench and push press in my garage in my normal clothes. Twenty minutes. You can fit your sprint work in later in the day, fifteen minutes or less.
The point is that the training that actually moves the needle for women through perimenopause and beyond is short, intense, and highly leveraged. It’s not the hour-long classes the fitness industry has been selling women for thirty years. Recovery is structured differently, too — women can typically push hard for two or three days before needing real recovery — and the way the menstrual cycle interacts with strength training means there are phases where you can drive hypertrophy harder and phases where the body has other priorities. The work is to understand the framework, then use it.
What about supplementation?
Creatine sits at the top of the list for women who lift, particularly through perimenopause and post-menopause. Women have lower endogenous creatine stores than men and creatine supplementation has more measurable benefits in trained women than the gym-floor folklore suggests. The full supplement protocol covers creatine, iron, the adaptogens, and DIM in detail.
The bigger picture is the one most women never get told. Strength training isn’t a vanity project, and it isn’t a niche pursuit for women who want to compete. It’s the closest thing modern medicine has to a longevity drug for women in their forties, fifties, sixties and beyond. The bulky myth has cost a generation of women access to it. The next generation seems less prepared to give it up so easily, and the data on healthy aging in women who lift will make the case for them.
The work, for everyone else, is to get past the cultural anxiety, find a barbell, and start.
Roar: How to Match Your Food and Fitness to Your Unique Female Physiology for Optimum Performance, Great Health, and a Strong, Lean Body for LifeandNext Level: Your Guide to Kicking Ass, Feeling Great, and Crushing Goals Through Menopause and Beyondby Dr Stacy Sims (Rodale) are out now. Visitdrstacysims.com.
Photography Getty
