What is fat?

Fat is one of the three main nutrients (macronutrients), alongside carbohydrates and protein. It serves as the body's most concentrated source of energy and is essential for numerous vital functions. Fat provides 9 kcal (37 kJ) per gram - more than twice as much energy as carbohydrates or protein.

But fat is much more than just an energy source: It plays a crucial role in cell structure, hormone production, nutrient absorption, and temperature regulation. Without fat, a healthy metabolism, strong immune defenses, and a properly functioning nervous system would not be possible.

Types of fats

Not all fats are the same - they differ in their chemical structure and effects on health.

1. Saturated fatty acids:

  • Found mainly in animal products (butter, meat, milk), as well as coconut and palm fat.

  • Are solid at room temperature.

  • Serve as an energy reserve and protective layer for organs, but should be consumed in moderation because excessive consumption is associated with elevated cholesterol levels.

2. Monounsaturated fatty acids:

  • Found, for example, in olive oil, avocados, nuts, and rapeseed oil.

  • Support cardiovascular health, help lower LDL cholesterol ("bad cholesterol"), and promote the absorption of fat-soluble vitamins.

3. Polyunsaturated fatty acids:

  • Include omega-3 and omega-6 fatty acids, which are essential - the body cannot produce them itself.

  • Sources: fatty fish (salmon, mackerel, herring), walnuts, flaxseeds, chia seeds, sunflower oil.

  • They support the heart, brain, eyes, and inflammation regulation.

4. Trans fatty acids:

  • They are produced through the industrial hydrogenation of oils or by heating them at high temperatures.

  • They are found mainly in processed foods, baked goods, and frying fats.

  • Should be strictly avoided because they promote cardiovascular disease.

Functions of fat in the body

1. Energy source and energy storage:
Fat is the body's most important energy store. It is stored in fat cells (adipocytes) and mobilized for energy when needed - especially during prolonged physical activity or lack of food.

2. Cell structure and protection:
Fats are a major component of cell membranes and provide stability, elasticity, and permeability. In addition, fatty tissue protects internal organs from impacts and cold.

3. Hormone production:
Fats are precursors for the production of important hormones and signaling molecules (e.g., steroid hormones such as estrogen and testosterone, as well as prostaglandins).

4. Absorption of fat-soluble vitamins:
Only fat enables the body to absorb, store, and utilize the vitamins A, D, E, and K.

5. Brain and nervous system:
The brain consists largely of fat. Omega-3 fatty acids (e.g., DHA) are particularly important for the development and function of the brain and nerves.

Benefits of a balanced fat intake

  • Provides long-lasting energy

  • Supports hormonal balance and fertility

  • Promotes the absorption of essential vitamins

  • Protects organs and cells

  • Supports skin, hair, and brain

  • Strengthens the cardiovascular system (with the right fat quality)

Recommended fat intake

According to the German Nutrition Society (DGE), approximately 30–35% of daily energy intake should come from fat. The following applies:

  • Saturated fats: < 10% of total energy

  • Unsaturated fats (especially omega-3): prioritize

  • Trans fats: avoid as much as possible

For example: With an energy requirement of 2000 kcal, about 65–75 g of fat per day should be consumed.

Possible consequences of deficiency or excess

Fat deficiency:

  • Dry skin, brittle hair

  • Hormonal disorders

  • Concentration problems

  • Deficiency of fat-soluble vitamins (A, D, E, K)

Excessive fat intake (especially saturated fats and trans fats):

  • Elevated blood lipids and cholesterol

  • Overweight

  • Increased risk of cardiovascular disease

Conclusion

Fat is essential for life – it supplies the body with energy, protects organs, regulates hormones, and supports the absorption of important vitamins. However, the quality of the fats consumed is crucial: healthy unsaturated fatty acids (e.g., from olive oil, nuts, and fish) should make up the majority of fat intake, while saturated fats and especially trans fats should be reduced as much as possible. A conscious balance of fats is therefore the foundation for health, performance, and well-being.

Sources

  1. German Nutrition Society (DGE). (2020): Fat intake and fatty acids – DGE recommendations.

  2. Mensink RP, et al. (2016): Effects of saturated, monounsaturated, and polyunsaturated fatty acids on serum lipids and lipoproteins. Am J Clin Nutr, 103(3), 708–718.

  3. Calder PC. (2015): Functional roles of fatty acids and their effects on human health. J Parenter Enteral Nutr, 39(1), 18S–32S.

  4. Mozaffarian D, Katan MB, Ascherio A, Stampfer MJ, Willett WC. (2006): Trans fatty acids and cardiovascular disease. N Engl J Med, 354(15), 1601–1613.