In theory, a good diet should give us most of what we need. Plenty of vegetables, enough protein, whole foods, regular oily fish, nuts, seeds, beans and whole grains. It sounds simple enough. 

But in practice, very few of us eat like that every day once you’ve layered in work, schedule pressures and the general business of life.  

You might start the morning with good intentions, then realise at 11am you've had two coffees and no breakfast. Lunch gets pushed between meetings and you grab some biscuits to keep energy up. You're stressed, so dinner becomes whatever is quickest rather than the lentil-and-roasted-vegetable situation you'd imagined. Or you're eating very “cleanly”, but rotating through the same salads ever week which are deceivingly low in nutrient density.  

Stress matters here, too. Not just because it increases mineral demands, but more so because of what it does to the way we live. Chronic stress disrupts sleep, alter appetite and affects digestion. It can mean more caffeine, more alcohol, less regular meals, and more cravings at night. And when we're under pressure, dietary variety is usually one of the first things to disappear. 

Then there are things we can't solve simply by trying harder. In the UK, we can't synthesise enough vitamin D from sunlight through the autumn and winter months. Some medications affect nutrient absorption or metabolism. Restrictive diets and fasting can make it harder to fit enough nutrition into the day. And our requirements shift with age, pregnancy, breastfeeding and training. 

So while food should always come first, “just eat a balanced diet” misses quite a lot of real life. Here are the biggest gaps.  

1. Fibre: The Gap is Enormous 

This is probably the clearest place to start. 

UK adults are advised to eat 30g of fibre every day. The latest National Diet and Nutrition Survey found adults average just 16.4g. This is a huge gap; only 4% of adults actually hit the recommendation. 

And when you look at a typical day, it's easy to see how it happens – even when the food is ‘healthy.’ 

Eggs on toast for breakfast, chicken and rice for lunch and salmon with a little broccoli for dinner is a pretty healthy day when you consider each meal, but it can be surprisingly low in fibre as a whole. 

Fibre needs to be much more intentional: increase beans, lentils, flax, fresh fruit, swap white grains for whole grains, and focus on nuts and seeds. But we shouldn't wait for the perfect diet before addressing a large, measurable gap, especially one that is as important as fibre.  

Fibre supports bowel health, but that's only part of the story. Higher-fibre diets are associated with blood sugar control, steadier energy, better cardiometabolic health and a lower risk of cardiovascular disease, type 2 diabetes and colorectal cancer. Diets high in fibre will also help inflammatory balance, mood, skin, and overall energy.  

Changing the way we eat takes time; research suggests it takes around three months for a new habit to become automatic. This is where a fibre supplement can be particularly useful: not instead of improving your diet, but while you improve it.  

Try This: Essential Fibre+ for 3 months while you solidify a high fibre diet in practice.  

2. Vitamin D: the one that food can't reliably solve 

Yes, there are some dietary sources - oily fish, egg yolks and fortified foods among them- but it's extremely difficult to obtain enough vitamin D from food alone. 

Our major source is sunlight. UVB exposure allows the skin to make vitamin D, which works well when the right sunlight is available – but not in Britain. From Autumn to early March, sunlight in the UK doesn't contain enough UVB for us to reliably synthesise the vitamin D we need. That's why UK guidance recommends that everyone consider taking  Vitamin D during the autumn and winter. Many practitioners suggest all year round

Vitamin D is important for calcium and phosphate regulation, bone and muscle health and normal immune function. So rather than viewing supplementation as a fad, Vitamin D3 is a good example of closing an essential dietary gap.  

Try This: Essential D3/K2 from now until spring.  

3. Minerals: a healthy-looking diet can still fall short 

Magnesium and potassium are interesting because, unlike vitamin D, they're readily available from food. Despite this, most women still aren't getting enough. 

Data from the National Det + Nutrition survey found that average intakes for both magnesium and potassium in women aged 19–64 are not being met.  

Again, when we look at how we eat regularly, this starts to make sense. Magnesium is found in foods such as pumpkin seeds, almonds, cashews, beans, lentils, whole grains and leafy greens. Potassium is abundant in potatoes, beans, lentils, vegetables, fruit, and fish. 

To achieve the RDA, we need to eat these foods regularly, and, Magnesium and Potassium just happen to be two minerals that become in higher demand during stress and exercise.  

These minerals are incredibly important because of how involved they are in so many fundamental metabolic and cognitive pathways.  

Magnesium contributes to energy metabolism, muscle and nervous-system function and electrolyte balance, helps with tiredness and fatigue, and is is essential to protein synthesis, while potassium is essential for the nervous system.  

You should definitely look to increase these nutrients from food - add the beans, get more greens onto the plate, and rotate your grains. But like fibre, you can use smart supplementation to fill the gap whilst you get the basics right or to cover your grounds during the run up to New Years.  

Try this: Cellular Hydration for a source of Magnesium + Potassium 

Try this: Essential Magnesium, for Magnesium alone.  

Bonus: Creatine - a different kind of nutritional gap 

Creatine doesn't fit neatly into the same category because there is no established RDA. 

Our bodies make creatine naturally and we obtain some through food, primarily meat and fish. So we're not talking about a classic nutrient deficiency. What is interesting is the difference between the amount we typically obtain through diet and the amounts used in research. 

The most studied supplemental dose is 3–5g of creatine monohydrate per day; and this is the dose range where the benefits are seen. To consistently get several grams from food, we’d need to eat substantial quantities of meat or fish every day – think 800grams. For vegetarians and vegans, dietary intake is lower still. 

Creatine is usually associated with men, muscles and gym bags, which has done it a disservice. At its most basic, creatine helps cells rapidly regenerate ATP - the immediately available energy our cells use to do work. This is important for muscle, but it also explains why researchers are increasingly interested in creatine beyond sports performance. 

In women, research has looked at strength, exercise performance and lean tissue, as well as potential applications in cognition and healthy ageing. There is also growing interest in different female life stages.  

But there is a useful distinction here. 

With fibre, we're trying to meet a clearly defined dietary recommendation. With vitamin D, we're compensating for a predictable environmental limitation. With minerals, we're addressing nutrients that are available in food but commonly under-consumed. 

With creatine, supplementation can provide a dose that is simply unrealistic to reproduce consistently through food. 

Try this: Essential Creatine 

Food first. Then fill the gaps that actually exist. 

The answer to modern nutrition isn’t taking handfuls of supplements forever. But “you can get everything from a balanced diet” is particularly useful either when the reality of modern life means that most of us aren’t.  

Most of us don't eat a textbook diet. We eat around work, children, travel, training, stress, appetite, take aways and whatever happens to be left in the fridge on Wednesday night. 

The more useful approach is to get the foundations right and then be specific. Eat enough plants and enough fibre. Build meals around genuinely nutrient-dense foods. Eat a wider variety of them. Pay attention to protein. Don't expect supplements to compensate for a poor diet, but use them as tools to fill the gaps.