5 Simple Ways to Kickstart your Metabolism after 40
I still remember the moment I realised my body had quietly shifted gears. I’d always been fairly active and mindful about my health, but as I hit my 40s, I noticed subtle changes: a little belly pouch that wouldn’t budge, dips in energy that hit mid-afternoon, and brain fog that left me staring at my screen longer than I’d like to admit.
Sound familiar?
The truth is, after 40 our metabolism naturally slows down. Hormonal changes, stress, and lifestyle habits all play a part. But here’s the good news: you don’t need to overhaul your entire life or spend hours in the gym to feel the difference. Small, consistent tweaks - what I like to call Simple Biohacks - can make a world of difference.
Here are five practical ways I’ve used to give my metabolism a nudge after 40:
1. Start your morning with protein (and a glass of water)
For years I was a “coffee first” kind of person. But when I started my day with protein, like eggs, Greek yoghurt, or a protein smoothie, I noticed my energy lasted longer and I wasn’t raiding the snack cupboard at 10am. Pairing it with a big glass of water first thing also rehydrates your body after sleep and wakes up your digestion.
Why it works: Protein requires more energy to digest, helping to kickstart your metabolism. It also keeps you fuller for longer and stabilises blood sugar, which means fewer spikes and dips.
2. Micro-movements throughout the day
We often think we need long workouts to make a difference, but the truth is: little movements, done often, add up. I love building “exercise snacks” into my day - a little bit like multi-tasking. While brushing my teeth, I do squats. When I’m at my desk or even on the sofa, I do calf raises (lift your heels up and down, keeping your toes on the floor and repeat). These micro-movements strengthen muscles without stealing time from your day.
Why it works: Muscle is your metabolic engine. Even small amounts of muscle engagement throughout the day increase calorie burn and improve circulation.
3. Upgrade your snacks
I used to reach for biscuits or crisps around 3 p.m.—and then wondered why I had no energy by 4. Now, I choose smarter options: almonds, apple slices with nut butter, a couple of squares of dark chocolate or a cup of bone broth.
Why it works: Balanced snacks with protein, fibre, and healthy fats help stabilise blood sugar levels. That means fewer cravings, less energy dip, and a metabolism that ticks along more smoothly.
4. Cold showers (Made easier!)
I’ll admit, this one felt extreme at first. But here’s the trick: you don’t need to plunge into an ice bath or dive in head first into a cold shower. Simply finish your usual hot shower with 20–30 seconds of cold water. It’s short, sharp, and incredibly effective. It may feel challenging at first, but trust me, it gets easier! Over time, this simple hack helps keep your metabolism and resilience sharp.
Why it works: Cold exposure activates brown fat (the “good” fat) which burns energy to generate heat. It also boosts circulation and can give your metabolism a natural kickstart. Plus, it’s an instant mood-lifter!
5. Prioritise sleep like it’s a meeting you can’t miss
Sleep is the secret weapon no one talks about enough. A proper wind-down at least one hour before bed makes all the difference. I switch off screens, dim the lights, read a book, and sometimes even put my legs up against the wall for 2 minutes to help circulation and calm my nervous system. By 10.30pm, lights are out.
Why it works: Poor sleep disrupts hunger and stress hormones (ghrelin and cortisol), making you crave high-calorie foods and slowing down your metabolism. Good sleep resets your system, balances hormones, and makes all the other biohacks more
My Takeaway
After 40, your body isn’t broken, it’s simply asking for more thoughtful care. These five Simple Biohacks are proof that small, realistic changes can reawaken your metabolism, boost your energy, and help you feel like yourself again.
Start with one. Add another when you’re ready. The power lies in consistency.
Your future self will thank you.
About the author
This article was written by Wendy Schoonjans, guest contributor to Aeons and founder of Simple Biohacks. With a passion for women’s health, she empowers women over 40 to feel energised, balanced, and confident. Through practical biohacks, natural supplements, and accessible education, she bridges the gap between science and everyday life - helping women thrive through life’s transitions.