Let’s just get one thing straight – I didn’t start intermittent fasting in my 40’s because it’s one of the ‘in’ things.
I started because I felt off. Tired more often than not, bloated by lunchtime, and in a constant cycle of either craving sugar or trying not to eat it. Oh, and let’s not forget the rollercoaster that is perimenopause – mood swings, brain fog, sleep disruptions and the dreaded lower belly fat.
So, like many women, I started searching for something sustainable. Something that wasn’t a fad diet or based on 1,200 calories of rice cakes and lettuce.
That’s when I discovered fasting and it changed more than just my eating habits.
What Is Intermittent Fasting and Why Try It in Your 40’s?
Intermittent fasting (IF) is simply eating within a set window of time, then fasting (not eating) for the rest of the day. No calorie counting. No cutting out entire food groups. Just a rhythm that gives your body time to rest and reset.
After 40, our hormones start shifting, especially estrogen, progesterone, and insulin. These changes can affect everything from energy and mood to metabolism and appetite. Intermittent fasting – when done correctly – can support hormonal balance, reduce inflammation, and help regulate blood sugar.
But (and this is a big one) not all fasting styles work for women in perimenopause or beyond. In fact, overdoing it can do more harm than good, so it’s really important that you don’t throw yourself in headlong. Easing in gradually gets you used to it and if you’re anything like me, you’ll be surprised with how much you actually want to do it. Dare I say that I quite enjoy some of my fasting days? It can be liberating to be freed from the need to feed yourself three times a day and snack in between…
That’s why I started slow, experimented and found what actually worked for me.
What I Do: The 16:8 Method (With the Occasional 24-Hour Fast)
I started with the 16:8 method – which means fasting for 16 hours, and eating all meals within an 8-hour window. For me, that usually looks like 12.30pm to 8.30pm.
It felt natural. I’d already lost my appetite for big breakfasts, and I was tired of eating first thing in the morning ‘because breakfast is the most important meal of the day’. Did you know that Kellogg’s devised that slogan in the 1970’s to sell cornflakes? Yes, a marketing campaign launched before I was even born that has stuck with me my whole life. Don’t get me wrong, I still love breakfast and on holiday I absolutely never go without (hello eggs and bacon cooked for me) but it turns out that listening to your body beats following outdated food rules and misbeliefs.
On days when I feel like I need a reset – maybe after a holiday or a heavy weekend – I’ll throw in a 24-hour fast, usually from dinner one day to dinner the next. It’s not extreme. I still drink water, fatty coffee and electrolytes if I need them. I’ll only do it when it feels right and it fits around what I’m doing.
What Intermittent Fasting Helped With in My 40’s
1. Bloating and Digestion
Let’s be honest: midlife bloat is a thing. IF gave my digestive system a break and dramatically reduced the constant ‘am I six months pregnant or just full?’ feeling.
2. Blood Sugar and Cravings
No more 3pm sugar crashes. My energy became more stable, my cravings decreased and I stopped obsessing over snacks. We all know that we often grab snacks out of boredom but when you start to understand how snacks affect your metabolism, it all starts to become clear.
3. Mental Clarity and Focus
It surprised me, but fasting actually helped clear the brain fog. I get more done during my fasted hours than I did when I was munching through the morning.
4. A Better Relationship with Food
Instead of grazing all day and feeling guilty, I became more intentional. I eat nourishing meals, enjoy them, and move on. No more food guilt.
What Didn’t Work (AKA My Fasting Fails)
Fasting Through Hormonal Hell
Trying to fast on the first day of my period? Huge mistake. I was exhausted, hungry, and moody. Now I know: your cycle matters. I ease up on fasting the week before and during my period.
Fasting on Little Sleep or High Stress
Fasting when you’re already exhausted just pushes your body further into stress mode. I learned to adjust and listen to what my body actually needs, not just stick to a schedule for the sake of it.
Not Eating Enough During the Eating Window
At first, I must admit that I underate. I treated the 8-hour window like a ‘mini diet’ and ended up ravenous the next day, which is never a good idea and will undo all that you have done. Now, I prioritise protein, healthy fats, and fibre, and make sure I’m properly fuelled. Keeping satiated is definitely the key here.
Hormones, Women & Fasting: What You Should Know
Here’s the truth: intermittent fasting can be powerful – but it’s not a one-size-fits-all solution. Women in their 40’s need to approach fasting differently than men or younger women.
When done right, fasting can:
-
Improve insulin sensitivity
-
Reduce inflammation
-
Support oestrogen detox
-
Help regulate cortisol levels
But if you fast too long, too often, or without enough fuel, it can:
-
Disrupt your thyroid function
-
Raise cortisol (stress hormone)
-
Affect your menstrual cycle
-
Increase fatigue and irritability
That’s why I treat intermittent fasting like a tool, not a rulebook. I adjust it based on:
-
Where I am in my cycle
-
How I slept
-
My stress levels
-
Whether I’m working out
Tips for Women Over 40 Starting Intermittent Fasting
-
Start small. Try 12:12 or 14:10 before jumping into 16:8, if you’re worried it will be too long to go without food initially.
-
Track your cycle. You may need to ease up during PMS or menstruation.
-
Hydrate. Water, herbal teas, and electrolytes are essential.
-
Break your fast gently. Choose real food – think eggs, greens, good fats and protein. My favourite way to break a fast at lunch time is poached eggs and smashed avocado on sourdough bread, along with some kombucha!
-
Don’t push through hunger if you feel weak, dizzy or anxious. That’s your body trying to tell you that you’re pushing yourself too far, so take the cues that something is running low in your system and remember you are probably not drinking enough water, so always start with that.
-
Focus on nourishment, not restriction. It’s important to remember that this is about supporting your body – not punishing it.
Final Thoughts: This Is a Lifestyle, Not a Diet
Intermittent fasting over 40 isn’t about chasing some unrealistic ideal. For me, it’s been about finding a rhythm that helps me feel energised, clear-headed, and in tune with my body.
I still enjoy food. I still eat pizza. I still have days where I say ‘sod it’ and eat biscuits and treats and that’s okay. I will never be a sugar free person, I don’t want to go without forever – what’s the point? I get that it’s healthier but a life without cakes, chocolate and cheesecake is a miserable one to me. What I do now though is not instinctively grab biscuits as I find it’s just habit, so one every now and then is just fine to me.
The beauty of intermittent fasting in midlife is that it’s flexible. It gives you space to nourish yourself while also giving your body time to do what it’s brilliantly designed to do – rest, repair, and thrive. It’s honestly been such an eye opener for me and has helped develop my relationship with food for the better.
Have you tried intermittent fasting in your 40’s? I’d love to know how you have found it 🙂
Leave a Comment