During perimenopause, it can feel like the rules of your own body change overnight.
"I don't fit into my pants from last year anymore." "I'm trying to eat "clean" and exercise but the scale keeps going up and up and up." "I don't recognize my body anymore."
These are what women sitting across from my at my Newmarket and Innisfil office say to me all the time.
They feel like nothing has changed, yet everything has changed.
And, to be honest, there is a lot that has changed and will continue to change.
While these shifts can feel frustrating, midlife is actually one of the most powerful windows of opportunity to protect your metabolism and heart for the rest of your life.
Let's get into what's actually happening to your metabolism during perimenopause, how to start working with your changing body, and why non-scale wins matter far more than the number on your bathroom scale.
During the menopause transition, declining estrogen levels shift where your body stores fat. Rather than storing fat in the hips and thighs and wherever you're genetically predisposed, fat storage begins to favour the abdominal area. Some of you may not notice a change in your weight on the scale but notice a change in your abdominal area.
Clinically, it's essential to distinguish between two types of abdominal fat:
This second type of fat, visceral fat, is the primary concern for midlife health because it drives increases insulin resistance, contributes to inflammation and fatty liver disease, and elevates overall cardiometabolic risk.
The biggest increase in fat mass tends to heppen in the 4-year window surrounding your final menstrual period, as in: the 2 years before and 2 years after your final period ever.
On average, hormonal shifts alone account for only a small percentage of weight gain. Midlife weight changes are typically a combination of hormonal shifts, natural chronological ageing, and subtle lifestyle changes that accumulate over time.
Patients usually ask this exasperatedly!
It's not that the fundamental rules of healthy living or the math of your metabolism have changed, but rather that your margin for error gets tighter in midlife.
In your 20s and 30s, your body can "get away" with inconsistent habits. In perimenopause, subtle changes in stress, recovery, and daily movement begin to have a bigger impact. Here's some of the things that are often going on:
Metabolic health refers to how effectively your body processes energy, measured via blood sugar levels, insulin sensitivity, liver health, cholesterol profiles, and waist circumference. Here's a blog post on metabolism if you'd like to understand that a bit better.)
Cardiovascular Health is the health of your heart and blood vessels, specifically monitoring for conditions like atherosclerotic cardiovascular disease (plaque buildup in the arteries) that can lead to a heart attack.
Perimenopause is a period of accelerated cardiometabolic change. Estrogen helps keep blood vessels flexible, exerts anti-inflammatory effects inside your arteries, and supports a healthy cholesterol profile. As estrogen declines, arterial stiffness increases, LDL cholesterol often rises, and blood sugar regulation becomes more challenging. And, like I mentioned earlier, visceral fat around the midsection also increases. All of this is connected!
Catching these changes early in your 40s provides a a big opportunity for implementing lifestyle change and preventive care, especially for those of you at high risk due to your past or family history. The steepest change in cardiometabolic health happens in those 2 years before after your final period ever.
Scale weight is your gravitational pull to the earth. In perimenopause, you can be the same weight but still have more visceral fat and less muscle and bone mass than you once did. The weight on the scale is not a proxy for your health.
BMI, or your body mass index, is a calculation of your height and weight taken together. You could be extremely muscular and have a high BMI. You could have a "normal" BMI and have fatty liver disease.
We can use these metrics (when appropriate), but we shouldn't only be using these metrics. We've taken them way out of proportion and have connected our worth these numbers.
Waist circumference is often a better metric to assess for cardiometabolic risk (we measure this at the top of the hip bones). A waist circumference of less than 88 cm (35 inches) for women is widely used as a guiding marker to screen for excess visceral fat. Body composition tracking can be done with a tools like DEXA scans or bioelectrical impedance (such as InBody scans) to evaluate muscle mass and body fat percentage separately. Even then, body composition is one component of your health and longevity. We take this alongside other cardiometabolic markers and non-scale wins, like:
No. The claim that exercise-induced cortisol causes midlife belly fat is just not true.
Stress affects us in many ways. And, yes, while cortisol is our "stress hormone", we need it to function. It naturally fluctuates.
While high-intensity workouts or strength training temporarily raise cortisol, this is a normal, healthy physiological response to physical stress. Once your workout ends, cortisol levels naturally decline. In fact, all kinds of exercise improve long-term cortisol and nervous system regulation. Here's a full blog post on cortisol.
Pathologizing this normal process causes unnecessary fear, leading many women to abandon effective cardiovascular exercise in favor of walking only. While daily walking is fantastic for health and I encourage you to do more, challenging your heart with higher-intensity movement is deeply beneficial for vascular health, cognitive function, and metabolic resilience. In fact, high-intensity interval training (HIIT) can actually be the most beneficial form of exercise to decrease body fat mass ... just saying!
You don't need expensive supplements or extreme diets to protect or "support" your midlife metabolism. Focus on these strategies:
Bodies change. They're supposed to!
Midlife metabolic changes are real ... as are age-related metabolic changes.
Taking charge of your health and working on making yourself comfortable in your body are worthy goals. But, remember, weight is multifaceted. Your weight is NOT a proxy for your health and it is NOT a reflection of your worth (despite all the diet culture BS and patriarchal (and impossible!) "beauty standards" that are shoved down our throats our whole lives).
By shifting your focus away from restrictive dieting, shrinking all parts of you, and the bathroom scale, and focusing more toward building muscle and increasing your fitness, fuelling with fibre, and monitoring your cardiometabolic numbers, you can protect your heart and metabolism for decades to come.
And, if you're looking for a Menopause Society Certfiied Practitioner in Ontario, especially in Newmarket or Innisfil (or virtual), feel free to book an appointment here.
This post was inspired by a conversation I had with Dr. Daiana Castleman, ND MSCP as part of The Perimenopause Summit in Sept 2026--you can put yourself on the waitlist for next year.
References Ananda Chatterjee et al. 2022. PMID: 34932890. CSEP Guidelines. Canadian 24-Hour Movement Guidelines for Adults aged 18-64 years. Reynolds et al. 2022. PMID: 35449060. McNulty et al. 2025. PMID: 40992413.
