Have you ever wondered whether going keto or trying intermittent fasting is the magic key to finally losing
stubborn weight after 35?
I see so many women get incredible results with these approaches… but I’ve also seen them backfire, especially when thyroid function or stress hormones (like cortisol) are already out of balance.
So let’s break down the pros and cons of both, so you can decide what’s right for your body.
Why Women Over 35 Need a Different Approach
Once we hit our mid-30s and beyond, our metabolism starts to shift. Hormones like estrogen, progesterone, and thyroid hormones naturally decline, while cortisol (our stress hormone) often rises.
That means diets that worked in your 20s—or even 10 years ago—don’t always work the same way now.
Our bodies become more sensitive to stress, more resistant to insulin, and more protective of fat stores. (yes this time of life can be sooo fun!)
The Keto Diet: Pros & Cons
Pros:
- Supports insulin sensitivity
- Reduces appetite
- Sharpens brain function (our brain uses ketones as an energy source)
Cons:
- Can stress the thyroid and affect healthy conversion of T4 to T3
- Raises cortisol in some women
- Low fibre affects gut health - not great if you already experience gut symptoms
- Hard to sustain long term, with rebound weight gain risk
Intermittent Fasting: Pros & Cons
Pros:
- Regulates blood sugar
- Reduces snacking and bloating
- Gentle entry point, can gradually extend fasting windows at your pace
Cons:
- May spike cortisol in some women
- Skipping breakfast worsens thyroid fatigue (you may not even know your thyroid is involved!)
- Can lead to overeating later in the day
My Clinical Perspective
In practice, I’ve seen both keto and intermittent fasting work beautifully—but I’ve also seen them stall
progress. The difference comes down to the fact that every woman is an individual.
If you’re already juggling high stress, thyroid shifts, or perimenopause symptoms, strict keto or long fasting
windows may do more harm than good. This is where we need to work out what is going to be best for your physiology at this point in time and try a strategy that isn’t going to create more stress, and help you achieve your goals.
The Bottom Line
Keto and intermittent fasting can both be useful tools, but neither is a one-size-fits-all solution. The real key is understanding what your body needs to balance hormones, lower stress, and unlock fat loss.
Want a downloadable freebie to get you started? Take my free Metabolism Detective Quiz and uncover the hidden blocks that may be keeping you from your goals. Look for the Metabolism Detective Tab on my homepage for more details.
