Fundamentals of Nutrition: A Clear Overview for Beginners

Food is more than just enjoyment for us—it is the essential foundation for our bodies to function, grow, and regenerate. But what exactly happens inside when we eat something? Why do we need certain nutrients, and how are all these processes interconnected? In this article, I’ll give you a friendly overview of the key concepts of nutrition, energy metabolism in the body, and why personalized nutrition planning is so important.

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Why does our body need energy and nutrients?

Our body is like a highly complex machine. For all organs, muscles, and even our brain to work properly, we need energy—often called fuel. We obtain this energy from the foods we consume daily.

When we eat, the food is broken down in our digestive system—similar to an engine processing fuel. The main "fuels" are the so-called macronutrients: carbohydrates, fats, and proteins. Additionally, there are micronutrients like vitamins and minerals, which are essential for many bodily processes, even though they are needed in smaller quantities.

The details of energy: where does it come from, and what do we need it for?

Our body uses nutrients to produce ATP (adenosine triphosphate)—the real energy each cell needs to perform its functions. This process occurs continuously: energy is released to, for example, make the heart beat, move muscles, or allow the brain to think.

It is important to know that not all energy is directly usable. During conversion, some energy is lost—mostly as heat. That’s why we also feel that our bodies emit a lot of heat, especially during physical activity.

How much energy does a person need?

Individual energy requirements depend on many factors, such as age, gender, weight, muscle mass, hormonal status, ambient temperature, and lifestyle. For example, an active person needs significantly more energy than someone who sits a lot.

Here are some examples:

Jessica is 30 years old, works in an office, and is quite sedentary. Her daily energy requirement is about 1,800 calories.
Tom is 25, works as a craftsman, and is very active. His needs amount to roughly 2,500 calories.

The difference mainly comes down to activity level and muscle mass.

Basal metabolic rate and active energy expenditure—two main factors of energy consumption

Basal metabolic rate (BMR) is the amount of energy your body needs at rest to maintain vital functions like heartbeat, breathing, digestion, and cell growth.

Active energy expenditure refers to the calories burned through activities like walking, sports, housework, or even mental work.

An example:

Imagine you spend the whole day at home. Your BMR consumes energy, and depending on how active you are, your total requirement increases. If you go for a short jog in the evening, your body will use more energy.

Suppose you weigh 70 kg. Your BMR is roughly 70 kg × 24 calories (per kg, per day), which equals about 1,680 calories. With activity, your needs can rise to 2,000 or even 2,200 calories.

How much energy does food provide?

Every intake of food provides energy, measured in calories by your body.

Carbohydrates (e.g., bread, pasta): about 4 calories per gram.
Fats (e.g., oils, nuts): about 9 calories per gram.
Proteins (e.g., meat, legumes): about 4 calories per gram.

An example:

An apple has about 80 calories, mainly from carbohydrates. A tablespoon of oil provides around 120 calories because fats are especially energy-dense.

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Digestion and energy: how efficient is the process?

Our body is quite effective at converting food into usable energy. However, some energy is lost during processing—for example, about 10% of the energy from food intake is excreted through stool, urine, or heat.

Another factor is thermogenesis: the process where the body expends energy to digest food, releasing it as heat. This occurs mainly with proteins, while fats result in the least losses.

In short: not all calories consumed are utilised exactly as energy; some are lost during digestion.

Vitamins and minerals – small helpers with a big impact

Whether vitamin C for the immune system or calcium for healthy teeth and bones—micronutrients are essential for many body functions. They support energy regulation, promote regeneration, and strengthen the immune system. Since needs vary across different life phases, a varied diet with diverse foods is particularly important.

Important micronutrients at a glance

Vitamin D: for bone health and the immune system
Iron: for oxygen transport in the blood
Magnesium: for muscle and nerve function
Zinc: supports healing and immune defense

Why is personalized nutrition so important?

Although there are fundamental principles of nutrition, every person is unique. Age, gender, muscle mass, lifestyle, preferences, and health status influence how much energy you need and what works best for you.

Imagine trying to follow a diet based on general recommendations meant for someone else. It’s like a standard recipe for everyone—it might work for some but rarely leads to lasting success or could even be harmful.

That’s why individual nutritional planning is crucial: it considers your preferences, goals, life circumstances, and how you feel when eating. When you enjoy your food and feel good doing so, you're much more likely to stick with your diet long-term.

My approach at OptiMind

At OptiMind, I focus precisely on this individualized approach. It’s not just about how many calories you need or how you distribute your macronutrients. It’s important to understand your personal preferences, consider your goals, and—most importantly—preserve the joy of eating.

Because nutrition should not be a mere obligation but a building block for your wellbeing, health, and quality of life. That’s why I work with you to develop strategies that fit your daily life, respect your habits, and motivate you over the long term.

Conclusion – Nutrition is personal; concepts are few, methods are many

In summary: There are basic principles of nutrition, but the key to success lies in personal adaptation. Whether you want to lose weight, build muscle, or just live healthier—understanding the fundamental concepts is the foundation.

However, it’s the personalized implementation, tailored to your preferences and life circumstances, that makes the real difference. Concepts are few, methods are many—just like in fitness training, where a few core principles exist, but the methods to apply them are diverse and individual.

If you're interested in designing your nutrition plan in a personal and sustainable way, I would be happy to help you find the best approach for you.

If you have any questions or would like personal advice, just write to me! I look forward to supporting you on your journey to a healthy, joyful diet.

Note: This article provides a basic introduction. For personalized advice, I recommend consulting a nutritionist or health professional.

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About the author: Helen Hammelberg

Psychologist, fitness trainer, nutritionist & founder of OptiMind

With a holistic approach, Helen supports people in recognizing and developing their full potential - be it mentally, physically or spiritually. Her approach is based on a deep appreciation for the individual needs of each person and the belief that everyone has the ability to positively shape their lives.

The OptiMind principle reflects a strongly client-centred approach as well as a long-term and process-oriented way of thinking to support your individual well-being and maximise your performance.

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