Why Your Calorie Deficit Isn’t Working in Menopause (And Why That’s Actually Good News)
Part 1 of a 3-part series on midlife metabolism — what’s actually changing, why, and what you can do about it.
You’ve done everything right. You’ve stayed in a calorie deficit, logged your food religiously, and followed the formula to the letter like your life depended on it. And yet, the scale isn’t budging at all.
You think something must be wrong with you to have yet another diet plan fail. Something’s wrong, alright. But it’s not you. Here’s the twist: the formula the entire diet industry has been using for generations might be the one that’s off, not you.
A new study just gave us some real validation on this, and it made me think about a bigger pattern. So many of the “gold standard” numbers we’ve been measuring ourselves against never actually included us in the first place.
What the researchers actually did
Researchers took a group of perimenopausal women and measured their actual resting calorie burn using a gold-standard method — the kind where you breathe into a machine and it tells you, definitively, what your body is doing. Then they compared that real number to what six of the most commonly used calorie formulas would have predicted. These are the same types of equations behind most calculators you’d find with a quick search.
The result? Most of the formulas overestimated how many calories these women actually burn at rest. On average, the gap was around 215 calories a day. For some formulas, it was closer to 400. Only two of the six came reasonably close to the real, measured number.
This research confirms what many of us in our midlife years already knew. Our metabolism is slowing down. And traditional diets aren’t working for us.
Okay, but isn’t this just about losing muscle?
This is the part I found most interesting. The assumption most of us have heard — including from me — is that our metabolism slows down in midlife primarily because we lose muscle mass, and muscle burns more calories than fat.
That’s true, muscle loss is real and it matters. But when the researchers checked how much muscle loss actually explained the gap between predicted and measured calories, the number was tiny. Barely 1 percent to 2 percent.
So something else is happening. Something about the way our metabolism shifts in perimenopause that we don’t fully understand yet (the research just isn’t there, sadly), and a formula built from just body weight, height, and age can’t capture it.
This isn’t the first tool that was never built for us
Here’s where it gets even more interesting to me. The calorie formula isn’t the only “objective” number the wellness industry has handed midlife women and told them to trust without question. Think about Body Mass Index, known as the BMI.
BMI feels like it’s been around forever, like some kind of medical law of nature. But a Belgian mathematician named Adolphe Quetelet actually developed it in the 1830s, and he wasn’t even a doctor. He wasn’t trying to measure anyone’s individual health, or body fat, or anything like that. He was trying to describe the “average man” for population statistics, using data he drew from the European men around him at the time.
And here’s the part that really puts it in perspective: that “average man” stood about 5’4″, weighed around 140 pounds, and had a life expectancy hovering around 40 (though the sheer number of babies and children who didn’t survive back then skews that figure hard — if you made it to adulthood, you had a real shot at your 60s or 70s).
Why This Still Matters for Your Body Today
Do you know a man like that? I don’t. I think my son met that average when he was 12 years old. That’s not a criticism of anyone in the 1830s, they were living the life their time and place handed them. But the “average” body Quetelet used to build the very foundation of BMI would look almost nothing like the men, let alone the women, walking around today.
BMI didn’t even become a healthcare screening tool until the 1970s, roughly 140 years later, when a researcher repurposed Quetelet’s formula for a completely different reason. Somewhere along the way, it went from “a rough population-level statistic based on 19th Century Belgian men” to “the number your doctor uses to sort you into a category,” without anyone updating the original data to reflect, well, actual diversity of bodies. Including menopausal ones.
I mean, do you really want your body compared to that of an 1830s Belgian man as the litmus test to how much you should weigh?
So we’ve spent decades measuring ourselves against tools that nobody ever designed with our bodies in mind in the first place. Not our hormones, not our life stage, not the specific way our metabolism moves through perimenopause and menopause. Hindsight is 20/20, and in hindsight, that’s a pretty significant blind spot to build a whole system of “healthy” and “unhealthy” around.
What a Calorie Deficit in Menopause Should Actually Look Like — And Why This Is Good News
If you’ve ever calculated a calorie deficit for menopause, followed it to the letter, and still felt confused about why your body wasn’t responding the way you expected, this is your explanation. It was never a discipline problem. The tools themselves have a blind spot, and that blind spot has been there from the very beginning.
This is exactly why, in my Midlife Metabolic Reset guide, I never wanted the calorie formula to be the main event. It’s a starting point, not a verdict. A rough sketch, not a set of orders.
Track These 3 Things Instead
What actually works better is the thing you already have access to, every single day: your own body’s feedback. Instead of white knuckling the day’s caloric intake, ask yourself and track these:
- Are you satisfied after meals, or still hunting for something an hour later?
- Is your energy steady through the afternoon, or crashing hard by three?
- Is your sleep improving as you make changes, or getting worse?
These are data points too, and unlike a formula built for a population that didn’t include you, they’re measuring you specifically.
This doesn’t mean numbers are useless. It means they’re one voice in the conversation, not the only one, and definitely not the original authority we’ve treated them as. Your body has been trying to tell you things all along. It might be worth trusting it a little more than the formula.
If you want the practical version of this, the plate method and the “don’t track, just swap” strategies in my free Midlife Metabolic Reset guide do exactly this: gentle structure without needing a perfect number.
This is part 1 of a 3-part series. Up next: if it’s not really about muscle loss, what else is slowing your metabolism down in menopause? And after that: does any of this mean the fight is unwinnable? (Spoiler: no.) Subscribe to the newsletter so you don’t miss the next two.
