Your 22 Most Important Questions About Healthy Eating – Answered by Our Experts

1. What is a healthy diet, actually?

A healthy diet is not a rulebook – it is more of a pattern. Anyone who regularly eats plenty of vegetables and fruit, pays attention to sufficient protein and high-quality fats, favours wholegrain products and largely avoids heavily processed foods has already understood the essentials. What matters is not the perfect meal, but the sum of habits over weeks and months. Someone who eats well on two days and undoes everything on five bad days will feel little difference. Someone who, on the other hand, eats solidly on five good days and treats themselves on two is doing their body something good in the long run.¹

2. Why is good nutritional supply so important?

Every second, millions of cells renew themselves in our body. Skin, gut, blood, immune system – all these tissues depend on continuous renewal. And every single one of these new cells needs building blocks to function properly. This is exactly where vitamins and trace elements come into play. They are not supporting actors in nutrition – they control and regulate metabolism at the cellular level. Without sufficient zinc, B vitamins, iron or vitamin D, fundamental processes run at a reduced capacity: energy production, immune defence, cell division, detoxification.

What is often underestimated: the body is a clever survival artist. When resources are scarce, it prioritises consistently – vital organs and functions are supplied first, everything else has to wait. What gets put on hold, we barely notice at first: recovery after exertion takes longer, performance declines gradually, the immune system responds more sluggishly, cells renew themselves more slowly and less precisely. These silent losses accumulate over years and can lay the foundation for health issues in the long run.²

In short: whoever nourishes their cells well lays the foundation for long-term wellbeing.

3. Do I need to count calories to eat healthily or lose weight?

For most people, counting calories permanently is neither necessary nor helpful. Anyone who constantly calculates easily loses sight of what really matters: the quality of food. Studies show that those who eat predominantly processed products for three weeks gain on average around 1 kg of body fat, blood lipids rise and reproductive hormones decline.³ 500 kilocalories from vegetables, pulses and healthy fats work completely differently in the body than 500 kilocalories from frozen pizza, toast or cereal bars.

Anyone who still wants to lose weight needs a slight calorie deficit – but not a meticulously calculated one. As a guide, eating a little less is sufficient: one handful fewer of crackers, skipping seconds or one less piece of cake per day is already enough. Anyone who reduces too drastically risks muscle loss, nutritional deficiencies and the well-known yo-yo effect.

4. Which foods should you eat every day?

A good foundation consists of vegetables, pulses, wholegrain products, nuts and seeds, high-quality oils and sufficient protein sources. One principle applies: variety is not a luxury, but a prerequisite. Even in Europe, where a wide variety of foods is available at any time, a large EPIC study with over 450,000 participants showed that those who eat with the greatest variety had significantly higher chances of living longer in good health.⁴

Different plants provide different types of fibre and micronutrients. Anyone who always reaches for the same varieties also consistently accepts the same nutritional gaps. A simple principle helps: aim for at least 30 different plants per week on your plate – and you are already on a very good path.⁵

5. Can I really boost my metabolism?

Yes – but not in the way many products and diets promise. Metabolism is not a simple switch that can be flipped with a particular food or pill. It is a complex system that responds to many signals simultaneously – and that is precisely the good news: there are several levers that really work.

One lever is muscle mass. Muscles consume energy even at rest. Anyone who trains regularly with weights permanently increases their basal metabolic rate. No superfood in the world can replace that.

Then there is nutrition. Sufficient protein has the highest so-called thermogenic effect – the body burns significantly more energy digesting protein than it does digesting fat or carbohydrates. Anyone who includes a good protein source at every meal actively supports their metabolism. Regular meal breaks also play a role: they give the body time to actually use stored energy, rather than constantly drawing on freshly consumed calories. In addition, biotin, chromium and zinc support the normal metabolism of macronutrients, while zinc also supports normal fatty acid and carbohydrate metabolism.

What permanently slows metabolism, on the other hand: chronic sleep deprivation, persistent stress, lack of movement and an insufficient supply of important micronutrients. Vitamins and trace elements are the control centres of metabolism – when they are missing, even the most efficient engine runs at reduced capacity.

Anyone who consistently works all these levers will genuinely influence their metabolism positively in the long term – not through a single trick, but through the interplay of many small, effective habits.

6. How much fruit and vegetables should you eat?

Five handfuls daily is a well-established guideline – but with every additional portion, the chance of healthy years of life increases. The effect continued up to 800 grams per day, which is around 10 portions. The authors estimate that millions of premature deaths could be prevented if people ate around 10 portions of fruit and vegetables.⁶

One principle applies: different varieties of vegetables and fruit provide different vitamins and secondary plant compounds that complement and enhance each other. Anyone who only ever eats cucumber and apple leaves a large part of the potential benefit on the table. The more colourful the plate, the better.

7. What are the healthiest foods?

The one superfood does not exist – and anyone who keeps searching for it will be repeatedly disappointed. What actually works is the combination: many different plant-based foods, pulses, wholegrain products, nuts, seeds and high-quality fats. Together they form a nutrient network that no single product can replace. Açaí berries from the supermarket are no better a choice than locally grown blueberries – just more expensive.

8. What do I need to do for my body to utilise proteins optimally?

A protein-rich diet alone is not enough. For the utilisation of protein and the building of the body's own proteins, the body needs folate, magnesium and zinc. Drinking sufficient fluids is equally important for the body to process protein effectively: around 30 ml of fluid per kilogram of body weight per day is ideal. Protein intake should also be spread as evenly as possible throughout the day, as the body can only process a certain amount of protein at one time.

9. Which diet helps with losing weight?

The most honest answer is: the one you can actually stick to. Radical diets work in the short term but almost always fail in the long run. What really helps is a diet that keeps you full and fits into everyday life: plenty of vegetables, sufficient protein, fibre-rich foods and significantly fewer heavily processed products. Anyone who additionally avoids snacking and maintains regular meal breaks gives their body the chance to actually use stored energy.

10. When do I need dietary supplements?

The theory and practice of healthy eating often diverge in everyday life. A varied diet can provide many nutrients. But stress, lack of time, ready meals, canteen food and similar factors can all leave their mark. Added to this are situations with increased demand: pregnancy, intensive sporting activity, medication use. In these cases, targeted supplementation can be sensible – not as a replacement for good nutrition, but as a reliable safety net.⁷

11. Which vitamins and minerals are most commonly lacking?

Vitamin D tops the list – particularly in the months with little sunshine, when the body's own production almost comes to a standstill. Iodine and selenium have, according to consumer protection organisations,⁷ been washed out of soils in many regions over the course of geological history. Iron primarily affects women of childbearing age, magnesium suffers with low wholegrain intake and chronic stress, and folate is particularly critical during pregnancy.

Several studies confirm this: the NVS II shows that large parts of the German population do not reach the recommended intake for several micronutrients through diet alone – particularly vitamin D, folate, iodine and, in women, iron.⁸ Biomarker data from the RKI⁹ confirm that these intake deficits for individual nutrients are also reflected in measurable blood and urine values.

12. Why are dietary supplements dosed so differently – and what is the optimal dosage?

Because dosage is always a question of the goal. There are fundamentally two approaches: the classical one aims to prevent a deficiency – that is, to prevent deficiency diseases such as scurvy or rickets. This is exactly what the so-called NRV reference values reflect, which are shown as a percentage on packaging. They define the minimum amount a healthy person needs in order not to be undersupplied – nothing more. The modern, preventive approach asks instead: what amount does the body need to be optimally supplied in the long term and to reduce the risk of disease? These amounts are generally higher – without reaching the range of overdosage.

Whether a dosage is too high or too low can therefore never be assessed in general terms. The decisive question is always: too high or too low – measured against which goal?

The motto "more is better" is nevertheless wrong when it comes to micronutrients. What counts is the right amount at the right time – and in most cases that means moderate dosages that cover actual requirements, rather than spectacular maximum doses that the body cannot utilise anyway.

13. Can I boost my immune system?

The immune system is not a simple switch that can be flipped with a single vitamin. Hundreds of complex processes interact with each other – and that is precisely what makes the difference. Anyone who relies solely on isolated individual nutrients falls short. Experts today agree: our immune defence benefits most from a stable basic supply of all immune-relevant micronutrients – including vitamin C, D, zinc, selenium and others.¹⁰ Even more effective is taking these nutrients as far as possible in their natural combination. This automatically brings additional valuable accompanying substances into play, such as antioxidants and secondary plant compounds. A varied diet with plenty of vegetables, fruit, herbs and high-quality oils is the best foundation for this.

14. Do children need dietary supplements?

The broccoli remains untouched, the peas are ignored, but the packet of rice cakes is empty again. Many parents put in a great deal of effort, and yet their children's diet in everyday life rarely matches what nutrition experts recommend. That is not a failure – it is simply reality.

The problem is this: particularly in childhood, the need for vitamins, trace elements and secondary plant compounds is especially high relative to body weight. The brain, immune system and bones are developing at a rapid pace. Studies such as the KiESEL study (2024) show that many children in Germany are significantly undersupplied with vitamin D, iron, iodine, folate and magnesium.¹¹

What experts recommend today: a well-dosed, broadly structured micronutrient supplement can, depending on the individual situation, serve as a sensible safety net – not as a replacement for a balanced diet, but as a pragmatic form of support where everyday life leaves gaps. For parents, this can offer an additional benefit: when basic nutritional needs are covered, children can get to know healthy foods in a more relaxed way – without pressure, without mealtime stress and without parents feeling guilty.

15. Can you get enough vitamin D through diet alone?

Only to a small extent. Vitamin D is barely present in meaningful amounts in food – fatty sea fish such as salmon or herring, egg yolk and certain mushrooms do provide some, but fall far short of covering daily requirements. The body can produce some itself in the skin when exposed to sunlight. However, in the months with little sunshine from October to March, this is not possible at our latitudes. Studies show that a large proportion of the population in Germany suffers from vitamin D deficiency, particularly in winter.

16. Sweeteners instead of sugar – a good idea?

At first glance it sounds tempting: enjoying sweetness without counting calories. But the reality is more complex. Sweeteners such as aspartame apparently do not satisfy the craving for sweetness as reliably as real sugar. In some people, increased cravings follow afterwards. Added to this is the fact that sweeteners are chemically produced and for many people do not fit with a natural diet. No proven health damage from moderate consumption has been established so far – but they are not a free pass either. Anyone who wants to eat less sweet food in the long term is better served by gradually retraining their sense of taste than by permanently satisfying it with sweeteners.

17. Are carbohydrates bad?

No – but it depends on which ones. High-quality carbohydrates from wholegrains, pulses, vegetables and fruit provide energy, valuable fibre and important micronutrients. They are digested slowly, keep blood sugar stable and keep you full for a long time. Most people already know that white toast, crisps and soft drinks are not nutritional powerhouses. The problem arises when this leads to the conclusion that carbohydrates should generally be avoided. Heavily processed, nutrient-poor carbohydrate sources primarily provide quick energy – followed by cravings. Anyone who cuts out wholefood carbohydrates across the board often loses an important source of nutrients. Anyone who cuts out the wrong sources, on the other hand, does themselves a great favour.

18. How can I benefit from intermittent fasting?

Intermittent fasting is popular – and what lies behind it is biologically quite remarkable. Anyone who regularly gives their body meal breaks activates a mechanism that barely gets a chance in an everyday life of constant snacking: autophagy. In this process, the body actively breaks down damaged cell components, recycles them and renews itself from within. Put simply: the body uses the break to tidy up and repair – a process that even earned cell researcher Yoshinori Ohsumi the Nobel Prize.

During meal breaks, insulin levels also fall, inflammatory markers decrease and the metabolism shifts into a regeneration mode that is simply not possible in continuous operation. Anyone who eats constantly barely allows these cleansing processes to get started.

The good news: you do not need to follow a strict fasting programme for this. Anyone who stops eating earlier in the evening and does not start breakfast too early already gives their body a valuable period of renewal. For many people, intermittent fasting is therefore not a miracle method, but a practical structure that gives the body what it needs anyway: time.

19. How can I put an anti-inflammatory diet into practice in everyday life?

Silent inflammation in the body is today considered one of the most important drivers of chronic diseases – from cardiovascular problems and diabetes to joint complaints and depression.

An anti-inflammatory diet addresses exactly this: many plant-based foods, plenty of antioxidants from vegetables and fruit, omega-3 fatty acids from fatty fish, linseed oil or walnuts, fibre and secondary plant compounds from colourful vegetables and wholegrains. What promotes inflammation, on the other hand: a lot of sugar, heavily processed foods, industrial vegetable oils and little movement.

The good news: an anti-inflammatory diet does not have to be a programme of deprivation – and it can be integrated into everyday life step by step, without changing everything at once. Small, consistent habits often achieve more than radical dietary overhauls that are rarely sustained for long.

In practical terms this means: olive oil instead of refined sunflower oil, a tablespoon of linseed oil in the salad dressing, a handful of walnuts as a snack, more pulses during the week and colourful vegetables as a fixed component of every meal. Anyone who additionally reduces sugar and heavily processed products is already giving their body a great deal.

20. What is the best diet for women over 40?

From midlife onwards, a number of things change: basal metabolic rate decreases, muscle mass is gradually lost without targeted training, and hormonal changes influence metabolism, bone density and energy balance. What this means for nutrition: protein becomes even more important – not only for muscles, but also for bones, skin and the immune system. Fibre helps to keep blood sugar stable and the gut functioning well. Since the body requires less energy overall, a high nutrient density becomes even more important. Anyone who thinks they simply need to eat less in order not to gain weight is missing the most important point: it is not about less – it is about better.

21. Which diet keeps you healthy for a long time?

Research into longevity and nutrition shows a remarkably consistent picture. People who are particularly healthy in old age do not follow a specific diet plan – but their eating patterns have much in common: many plant-based foods, little that is heavily processed, sufficient protein, high-quality fats and a good supply of micronutrients. Added to this are regular movement, social connection and a healthy approach to stress.

What research is making increasingly clear: a comprehensive micronutrient supply plays a greater role than long assumed. Current studies – including the widely noted COSMOS study by preventive medicine specialist JoAnn Manson – show that daily supplementation with a broadly structured micronutrient preparation can measurably slow biological ageing. The measured effects on cellular ageing markers correspond to a slowing of the biological ageing process of up to 10 to 20 percent. That is not a marginal effect – it is a compelling argument for taking daily micronutrient supply seriously.¹²

There is therefore no single longevity diet. But there is an attitude: anyone who nourishes their body well every day lays the foundation for healthy years – not at some point in the future, but now.

22. Which foods are good for my gut – and how can I really strengthen it?

The gut is one of the body's most regeneration-friendly organs: the cells of the intestinal lining renew themselves completely every two to three days. That is a remarkable achievement – and at the same time a continuous demand. For this constant renewal, the gut needs the right building blocks every day. Anyone who nourishes it well is not making a one-off investment, but permanently laying the foundation for an intact gut barrier, functioning digestion and a strong immune system. Biotin, niacin, vitamin A and B2 support the normal function of the intestinal mucosa.

Particularly valuable are prebiotic foods – those that serve as nourishment for gut bacteria and thereby actively support the microbiome: chicory, cabbage vegetables, onions, leek, pulses, oats, barley and linseed are among the best sources. Fermented foods such as natural yoghurt, kefir or sauerkraut additionally provide living bacterial cultures that directly enrich the gut flora.

Anyone who has previously eaten little fibre should increase their intake slowly. Too much too quickly overwhelms the gut and leads to bloating and discomfort – the gut flora needs time to adapt to the new nutritional foundation. Anyone who accompanies this adaptation patiently will feel after a few weeks what a well-nourished gut can actually achieve.