Macronutrients are the raw material. Micronutrients are the machinery.
Updated: Sep 10
The mighty power of the micro.
There's a conversation that happens in my clinic more often than any other.
Someone sits down and tells me they're doing everything right. They're training three or four times a week, they've got their protein up, they've cut the ultra-processed stuff and they are chuffed to report they're eating more vegetables! But they still feel flat. They are recovery takes days and the 3pm crash arrives like clockwork. And the bit that hurts most: after all that effort, progress in the gym has stalled.
Then they say the thing I hear every week: "I don't understand it. I'm doing all the right things." And usually they are. These are the people at the 6am class, week in, week out. The problem isn't what's going on their plate, it's what happens to it afterwards.
Most nutrition advice concentrates on dialling in your calories and macros, those all important proteins, carbohydrates and fats. That's not wrong, they matter enormously, and if you're getting them badly wrong, fixing them will change how you feel. But here's where I feel there's the missing link that rarely gets mentioned: your body can't actually use any of it without a supporting cast or what is known as the co-factors.
Protein doesn't become muscle by itself. Carbohydrate doesn't become usable energy by itself. Every one of those conversions is driven by enzymes, and enzymes don't work alone they need those cofactors: Magnesium, Zinc, B vitamins, Iron, Selenium.
Miss the cofactor, and the raw material just sits there. You've eaten the protein but your body simply can't do much with it. It's the difference between having ingredients and having a working kitchen. You can fill the fridge, but if the oven's broken, dinner isn't happening.
What that looks like in practice
The research speaks for itself on the topic. In one study, zinc-deficient young women were given a modest daily dose of zinc for four months. "Nothing else changed, no diet overhaul, no new training programme. Their resting metabolic rate increased substantially In one group, by nearly a thousand calories a day. That's not a diet plan, that's a mineral that was missing and replaced.
The same pattern shows up elsewhere. Iron-deficient female athletes given iron over eleven weeks saw their blood markers and their performance improve. Magnesium supplementation in people with poor sleep has been shown to improve insomnia scores.
None of these people were eating badly, they were short of something specific, and their physiology was operating inside that constraint.
Why "eating well" doesn't always solve it
Here's the part that surprises clients the most. There are three separate places this can go wrong, and eating well only addresses the first.
The intake gap. What actually reaches your plate. Even people who "eat well" tend to eat the "same well", the same five vegetables, the same three meals in rotation. It's the variety, not just quality, that drives micronutrient coverage.
The absorption gap. What your gut can actually take in. If digestion isn't working properly and you suffer from symptoms such as bloating, irregularity, inflammation, you can eat an excellent diet and absorb only a fraction of it. Some nutrients also compete for attention: calcium and iron interfere with each other, while vitamin C dramatically improves iron absorption. So timing and combinations matter.
The utilisation gap. What your body can do with it once it's in. Inflammation, stress, hormonal changes and heavy training loads all raise demand and alter how nutrients are used. Two people can eat identically and have completely different requirements.
You can be doing everything right at stage one and still come up short at stage three.
What actually helps
Rotate, don't just optimise. If you eat the same healthy meals every week, you get the same nutrients every week, and unfortunately, the same gaps. Varying your vegetables, proteins and grains does more for micronutrient status than perfecting any single meal.
Look after your gut. Absorption is the middle step and it's the one most people just skim the surface or skip altogether.. Fermented foods, fibre, adequate hydration, and taking symptoms like persistent bloating seriously rather than accepting them as "its always like that for me".
Stop guessing. This is the honest one. You cannot tell from how you feel which nutrient you're short of, the symptoms almost always overlap. Fatigue could be iron, B12, vitamin D, thyroid, blood sugar, sleep, or none of the above. Blood work turns that from speculation into information. You no longer fly blind, you have objective data and more importantly, a starting point from where you actually need support.
And it's worth knowing that "normal" on a standard test isn't the same as optimal. Reference ranges are built to catch disease, not to describe someone thriving. Plenty of people sit within range and feel nothing like themselves.
The point
If you're training hard, eating well, and still feel like you're pushing uphill, you're probably not doing anything wrong. You're more likely running into a constraint nobody has looked for. Your body isn't broken. It's asking for something it isn't getting. The good news is that this is findable and once you know what's missing, it's usually straightforward to fix.
I'm a Registered Nutritional Therapist in Watford, and this is the work I do: finding the constraint that's holding someone back, rather than adding more effort on top. If you'd like to find out more, book a free discovery call, it's a relaxed chat with no obligation.
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