What are three types of food

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Three main nutrients provide energy to the body: carbohydrates, fat and protein. But what significance do they actually have for the metabolism? What foods do they contain and how much should we consume every day?

Necessary energy sources

The body needs energy around the clock to maintain all functions. The so-called macro or main nutrients - carbohydrates, fat and protein - provide this energy. They are broken down in the digestive tract, transported via the blood to the body cells and consumed there. The energy content of a food is measured in kilocalories (kcal) or kilojoules (kJ). One gram of fat provides more than twice as much energy as the same amount of carbohydrates or protein.

1 g fat = 9 kcal (37 kJ)
1 g of carbohydrates = 4 kcal (17 kJ)
1 g protein = 4 kcal (17 kJ)

Food for the body and mind

Dietary fat is an important source of energy for humans and a carrier of flavors and aromas. The body can only absorb the fat-soluble vitamins A, D, E and K with the help of fat. In addition, fats provide essential fatty acids that the body cannot produce itself. Fat is therefore essential in moderation.

Protein provides the human body with amino acids and nitrogen. They are the building materials for cells and tissues, for example muscle fibers, organs and blood. But enzymes and various hormones such as insulin are also made up of amino acids. The body cannot produce some amino acids itself, so they have to be taken in with food.

Along with fat, carbohydrates are the most important sources of energy. They are the preferred source of energy, especially for the muscles and the brain. Carbohydrates consist of sugar molecules and occur in simple form in food, for example as grape sugar in sweets or as fructose in fruit, and in complex form, for example as starch in potatoes, pasta, rice and bread.

What is recommended?

Fat: As a source of fat, give preference to products with a high proportion of unsaturated fatty acids. These include vegetable oils such as rapeseed, walnut or olive oil, nuts and sea fish such as mackerel, herring or salmon. These lower the risk of cardiovascular diseases.

Protein: Good sources of protein are fish, meat, eggs, milk and dairy products as well as legumes. Grain products such as bread also contribute to the protein supply.

Carbohydrates: Grains, grain products, potatoes, vegetables and fruits are high in fiber and starchy. These products also contain many other nutrients such as vitamins, minerals and fiber, as well as phytochemicals. When it comes to cereal products, the whole grain variant is the best choice for your health and your hunger. Sweets and lemonades contain a high proportion of simple sugars, so less should be eaten.

Carbohydrates - fat - protein "50-30-20": more or less?

According to the recommendations of the German Nutrition Society (DGE), the main nutrients should be supplied in a certain ratio with food. This nutrient ratio represents a rough guideline for adults in order to provide the body with the necessary quantities of essential nutrients and at the same time to prevent nutrition-related diseases. The numbers serve only as a guide, as they are subject to individual fluctuations - depending on tolerance, likes and dislikes.

According to these recommendations, carbohydrates should make up the largest share of the total energy requirement of a person, namely more than 50% of the amount of energy every day.

The daily intake of fat depends on the amount of physical activity. People who sit mostly and do little exercise should consume a maximum of 30% of their daily calorie intake from fat. In physically active people, this value can increase up to 35%.

The recommended daily intake of protein is 0.8 g per kg of body weight. In a balanced mixed diet, this corresponds to a proportion of 9-11% of the energy supply. However, this is difficult to implement in practice. A protein intake of up to 15% or 2.0 g protein per kg body weight (as an upper limit value) is therefore acceptable.

An example: A 40-year-old woman who works in the office, i.e. mainly sits down, and who does not move much in her free time, needs 1800 kcal a day. According to the information given, your food should contain around 225 g of carbohydrates, 60 g of fat and up to 65 g of protein.

Author: Dr. Claudia Müller, act. Miriam Erhard
Photo: © Syda Productions - stock.adobe.com


Biesalski HK, Grimm P, Nowitzki-Grimm S: Pocket atlas nutrition. 7th edition, Thieme, Stuttgart 2017
DGE: Eating and drinking wholesome according to the 10 rules of the DGE (last accessed: 09/30/2020)
DGE: Energy: Guide values ​​for the average energy intake for people of different ages depending on the resting energy expenditure and physical activity (last accessed: 09/30/2020)
DGE: Selected questions and answers about protein and essential amino acids (last accessed: 09/30/2020)
DGE: Position Paper Selected Questions and Answers on Energy Supply, June 2015 (last accessed: September 30, 2020)
DGE: Position paper Guide values ​​for energy intake from carbohydrates and fat, January 2011 (last accessed: 09/30/2020)

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