Keto Killed My Metabolism: Why Low-Carb Diets Backfire After 40 I EP.9
I Tried Keto for 6 Months.
Lost Weight… My Period, My Energy, and My Sanity. Here's Why Low-Carb Diets Wreck Women Over 40 (And What to Do Instead)
Let me paint you a picture...
You start keto. You're motivated. You meal prep like a boss. You say no to bread, pasta, fruit… all of it. You track your macros like your life depends on it.
And for the first few weeks? It works. The scale drops. You feel like you've finally cracked the code. But then.
Your energy crashes. You can't think straight. Your workouts feel impossible. Your hair starts thinning. Your period gets weird… or just disappears. You're irritable, exhausted, obsessing over food 24/7.
And when you finally cave and eat a piece of fruit or a slice of bread? You gain five pounds overnight and spiral into guilt and shame.
Sound familiar?
Here's what nobody told you when they sold you on keto: Low-carb diets aren't designed for women over 40. And they can do serious damage to your hormones, your metabolism, and your mental health.
Why Keto Works for Men (But Wrecks Women Over 40)
Let's get one thing straight… keto can work. For some people. Usually men. Usually younger people with stable hormones and fast metabolisms.
But for women over 40? Completely different story.
Here's why.
Your hormones are already shifting. Estrogen is declining during perimenopause and menopause, which affects how your body regulates blood sugar, stores fat, and builds muscle. Your thyroid might be sluggish. Your cortisol is probably elevated from stress.
And then you throw keto into the mix.
Cutting carbs sends a signal to your body that you're in a famine. Your body responds by:
- Spiking cortisol (your stress hormone) to help you survive the "famine"
- Slowing your thyroid to conserve energy
- Disrupting your sex hormones (estrogen, progesterone, testosterone)
- Tanking your energy because your brain and muscles need carbs to function
The result? You lose weight at first… but you also lose your period, your energy, your mental clarity, and eventually… your metabolism.
The Hidden Hormone Disaster
Here's what keto does to your body when you're over 40.
1. It spikes cortisol (and keeps it elevated)
Cortisol is your stress hormone. A little bit is good… it helps you wake up in the morning and respond to challenges. But chronic elevated cortisol? That's a disaster.
High cortisol tells your body to store belly fat, break down muscle, disrupt sleep, and crave sugar. It also suppresses your thyroid and messes with your sex hormones.
Keto keeps cortisol elevated because your body interprets carb restriction as stress. And if you're already stressed from work, family, life? You're pouring gasoline on a fire.
2. It slows your thyroid
Your thyroid controls your metabolism. And it needs carbs to function properly.
When you cut carbs too low for too long, your thyroid slows down to conserve energy. This is called "adaptive thermogenesis"… your body's survival mechanism.
The problem? A slow thyroid means a slow metabolism. Which means you stop losing weight… and start gaining it back even though you're still restricting.
3. It disrupts your menstrual cycle
If you're still menstruating, keto can make your periods irregular, painful, or disappear completely. This is called hypothalamic amenorrhea… a sign that your body is under too much stress.
If you're in perimenopause or menopause, keto can make your symptoms worse. Hot flashes, mood swings, insomnia, brain fog… all of it.
4. It tanks your energy and mental clarity
Your brain runs on glucose. Yes, it can use ketones for fuel… but most women don't feel their best in ketosis.
You might experience brain fog, difficulty concentrating, mood swings, irritability, crushing fatigue. And if you're trying to work, take care of your family, and live your life? That's not sustainable.
Why You Gained It All Back (And Then Some)
Here's the part that breaks my heart.
You stuck with keto for months. You suffered through the exhaustion, the cravings, the social isolation of saying no to every carb. You lost weight.
And then… life happened. You went to a birthday party. You had a stressful week. You ate a sandwich.
And suddenly, the weight came roaring back. Five pounds. Ten pounds. More than you started with.
Why?
Because keto didn't fix your metabolism. It slowed it down.
When you restrict carbs for too long, your body adapts by becoming more efficient at storing fat and less efficient at burning it. So when you reintroduce carbs… even healthy carbs… your body holds onto them for dear life.
Add in the cortisol spike from the guilt and shame of "failing," and you've got a perfect storm for rapid weight regain.
It's not your fault. It's the diet.
My Keto Wake-Up Call
I tried keto. I really did.
I thought if I could just be disciplined enough, strict enough, perfect enough… it would work.
But my body had other plans.
My energy tanked. I couldn't get through a workout without feeling like I was going to pass out. My brain felt foggy. I was irritable and obsessing over food constantly. And I was so, so tired.
I kept telling myself it would get better. That I just needed to push through. That this was what it took to finally lose the weight.
But deep down, I knew something was wrong.
And when I ended up in the ER at 40+… burned out, exhausted, doing everything "right" and feeling like my body was betraying me… I realized the truth.
My body wasn't broken. The diet was.
What Your Body Actually Needs After 40
Here's what I learned when I stopped fighting my body and started listening to it.
You need carbs.
Not junk food. Not processed sugar. But real, whole-food carbs that fuel your hormones, your brain, your workouts, and your life.
Carbs aren't the enemy. They're essential.
Here's why:
1. Carbs support your thyroid
Your thyroid needs carbs to produce the hormones that regulate your metabolism. Without enough carbs, your thyroid slows down… and so does your metabolism.
Your thyroid needs carbs to produce the hormones that regulate your metabolism. Without enough carbs, your thyroid slows down… and so does your metabolism.
2. Carbs lower cortisol
Eating carbs signals to your body that you're safe, fed, not in a famine. This lowers cortisol and helps your body relax, recover, and burn fat.
Eating carbs signals to your body that you're safe, fed, not in a famine. This lowers cortisol and helps your body relax, recover, and burn fat.
3. Carbs fuel your workouts
Your muscles need glycogen (stored carbs) to perform. Without it, your workouts suffer… and so does your ability to build muscle and boost your metabolism.
Your muscles need glycogen (stored carbs) to perform. Without it, your workouts suffer… and so does your ability to build muscle and boost your metabolism.
4. Carbs support your mood and sleep
Carbs help your body produce serotonin (your happy hormone) and melatonin (your sleep hormone). Cut carbs too low, and you'll struggle with mood swings, anxiety, insomnia.
Carbs help your body produce serotonin (your happy hormone) and melatonin (your sleep hormone). Cut carbs too low, and you'll struggle with mood swings, anxiety, insomnia.
5. Carbs help you feel satisfied
When you include carbs in your meals, you feel fuller, more satisfied, less likely to binge or obsess over food.
When you include carbs in your meals, you feel fuller, more satisfied, less likely to binge or obsess over food.
What Sustainable Nutrition Actually Looks Like
If keto isn't the answer… what is?
Here's what works for women over 40.
Balanced, hormone-friendly nutrition that includes:
- Protein at every meal to support muscle, metabolism, satiety
- Healthy fats to support hormone production and brain health
- Complex carbs to fuel your thyroid, lower cortisol, give you energy
- Plenty of vegetables for fiber, vitamins, minerals
- Hydration to support every system in your body
No restriction. No deprivation. No obsessing over macros or cutting out entire food groups.
Just real food that nourishes your body and supports your hormones.
Here's what that looks like in practice:
Breakfast: Scrambled eggs with avocado and a slice of whole-grain toast. Or a protein smoothie with berries, spinach, oats.
Lunch: Grilled chicken salad with quinoa, roasted veggies, olive oil dressing.
Dinner: Baked salmon with sweet potato and steamed broccoli.
Snacks: Apple with almond butter. Greek yogurt with berries. Hummus and veggies.
Simple. Sustainable. Satisfying.
No guilt. No shame. No feeling like you're on a diet.
The Real Cost of Restriction
Here's what I want you to think about.
How much time have you spent restricting carbs, tracking macros, feeling guilty every time you ate something "off plan"?
How much energy have you lost trying to force your body into ketosis when it was screaming for balance?
How many social events have you skipped because you couldn't eat the food? How many times have you felt like a failure because you couldn't stick to a diet that was never designed for your body in the first place?
That's the real cost of keto.
Not just the money you spent on keto products and meal plans. But the time, energy, and joy you lost along the way.
What If You Could Eat Carbs and Still Lose Weight?
I know it sounds too good to be true.
But here's what happened when I stopped restricting carbs and started eating in a way that supported my hormones.
I lost weight. I gained energy. My brain fog lifted. My workouts got stronger. My mood stabilized. I stopped obsessing over food.
And I felt like myself again for the first time in years.
Not because I found another restrictive diet. But because I finally gave my body what it actually needed.
You can have this too.
Your Next Step
If you're tired of restriction… if you're ready to eat in a way that actually supports your body instead of fighting it… I've got something for you.
Download my free 2-day meal plan. It's designed specifically for women over 40 who want to eat real food, support their hormones, and feel energized… without cutting carbs or feeling deprived.
Balanced meals. Simple recipes. Real results.
And if you want more support… if you're ready to break free from the diet cycle once and for all… DM me "RESET" and let's talk about what your body actually needs right now.
You don't have to suffer to see results. You don't have to cut out entire food groups. You don't have to fight your body.
You just need to feed it what it's been asking for all along.
Let's do this together.
✨ Trish
P.S. – If you're coming off keto and struggling with rebound weight gain, hormone issues, or low energy… you're not alone. Let's talk. DM me "RESET" or book a free 30-minute discovery call at empiresunfitness.com and let's create a plan that helps your body heal and thrive.
Disclaimer: This content is for educational purposes only and reflects my experience as an ISSA Certified Personal Trainer. Always consult with your healthcare provider before making changes to your nutrition or fitness routine.