In this special series, guest writer Dr Libby Weaver shares her health insights. This week she discusses our metabolism.
“I think my metabolism is broken.”
It’s something I have heard countless times – usually from someone feeling exhausted, foggy or frustrated by clothes getting tighter, despite prioritising their nourishment
We often speak about metabolism as if it’s a static setting: fast, slow or somewhere in between. But metabolism is far more dynamic than that. It’s the sum of all the biochemical and physiological processes that keep you alive – converting food into energy, building and repairing tissues, regulating temperature and hormones, clearing waste and so much more.
When things aren’t feeling right in your body, it’s not because your metabolism has simply “stopped working”. It is responding to the information and conditions you give it through the way you eat, drink, move, sleep, breathe, think, believe and perceive.
And these conditions are more influential than we might initially realise. Things like persistent stress, sleep quantity and quality, movement, hormone production, nutrient intake – and even how much muscle you have – can profoundly affect how efficiently your metabolism operates. Inflammation and chronic stress, for example, prompt the release of cortisol, a hormone that can interfere with the production of active thyroid hormones, and disrupt blood sugar management, both of which can result in your body receiving a signal to store fat.
Poor or inadequate sleep disrupts the hormones that help regulate hunger and satiety, often leading to cravings, irregular appetite and sluggish energy. And not eating enough over the long term can also prompt your metabolism to slow down, as your body attempts to conserve energy in a perceived famine.
One of the most overlooked yet essential nutrients for a well-functioning metabolism is iron. Iron is needed for oxygen transport, energy production and proper thyroid function – all critical to metabolic health. If your iron levels are depleted, your cells simply cannot produce energy efficiently. You might feel fatigued, cold, foggy, anxious or flat, even if everything else in your routine seems sound.
That’s, in part, because iron fuels your mitochondria – the tiny engines in your cells that generate energy – and helps convert the inactive thyroid hormone (T4) into its active form (T3), which directly influences how your metabolism behaves. So, if you’re feeling sluggish and your iron stores are low, no amount of calorie counting or extra cardio will address the underlying issue. It’s not about willpower – it’s about biochemistry.
Modern life also plays a significant role in the perception that our metabolism is “off”. Many of us live largely sedentary lives – even when we exercise, we may spend the rest of the day sitting at a desk or in the car. Add to that the increasing reliance on ultra-processed foods, high in additives, preservatives and low in nutrients, and you have a recipe for metabolic confusion.
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Advertise with NZME.Our bodies are also dealing with perceived stressors from morning until night – constant notifications, unrelenting to-do lists, a string of meetings that didn’t go as planned, and external noise that keeps our nervous systems in a state of mild overdrive. In this state, your body isn’t broken – it’s simply prioritising survival. And survival isn’t about burning energy quickly. It’s about conserving what you have.
There’s also a common misconception that a fast metabolism is always better. While a faster metabolic rate can mean more energy (measured as kilojoules or calories) burned at rest, it isn’t necessarily healthier. Sometimes a fast metabolism is driven by an overactive thyroid which easily leads to anxiety, sleep disruptions, nutrient depletion or even muscle loss.
Instead of chasing speed, aim for equilibrium – a metabolism that is steady, responsive and supported by whole, real food, consistent movement, restorative sleep and a sense of inner calm and resilience.
So what can you do if your metabolism doesn’t feel like it’s working the way it once did?
The answer isn’t restriction or extremes – it’s nourishment and care. Feed your body enough food – especially food that looks like it came from the earth. Prioritise vegetables, protein and nourishing fats. Build and maintain muscle through regular resistance training – weights, pilates, yoga, gardening, farm work – which supports insulin sensitivity and naturally elevates your resting metabolic rate.
Make sleep a non-negotiable part of your health plan – not just because you feel better when you rest, but because your metabolism does too. And if you suspect iron may be an issue, don’t ignore the signs. Symptoms like fatigue, brain fog, hair loss, cold hands and feet, heavy periods or poor recovery from exercise can all point to suboptimal iron status.
Stress is another piece worth exploring – not just the dramatic or acute stressors, but the quiet, constant hum of perceived pressure so many of us carry.
Mental load, people-pleasing, perfectionism and a sense of never quite doing enough all add up. And when the body feels like it’s under siege, metabolism tends to slow, not because it’s failing, but because it’s adapting. Gently shifting your daily rhythm to include pauses, presence and moments of joy can have meaningful impacts.
The truth is, your metabolism isn’t broken – it’s doing exactly what it believes it needs to do to keep you alive. The good news? Small, consistent choices can shift the inputs and gradually recalibrate your body’s response. You don’t need to do everything at once. Often, the most profound changes begin with something small and simple that you can build on in a sustainable way.
If you’ve been feeling frustrated, tired or like your body isn’t responding the way it used to, take a long, slow breath. You’re not broken. You’re adaptive – and that’s powerful. Sometimes all your body needs is a change in rhythm, nourishment or support to start feeling like itself again. And when we stop pushing and start listening, that’s when the body begins to thrive.
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Advertise with NZME.More from Dr Libby
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Why Nutrition & Mental Health Are Linked. The foundation of how we feel is influenced by what we eat.
The Nutritional Fallout From High-Intensity Exercise. The hidden stresses of intense exercise on nutrition and health.
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How To Improve Your Sex Drive. If you’re noticing changes to libido, there are a few causes to consider.
How Can You Encourage A Restful Night’s Sleep? Is sleep evading you? Dr Libby has solutions.
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