Cortisol is often referred to as the "stress hormone," but in the context of nutrition, it can also be called the "hunger hormone" — especially in the sense that its release signals the body to mobilize energy.
How it works at the physiological level
The primary task of cortisol is to provide the body with fuel. It raises blood glucose levels by stimulating gluconeogenesis — the process of synthesizing glucose from non-carbohydrate sources, primarily from amino acids.
If amino acids are not obtained from food (for example, in cases of protein deficiency), cortisol activates the catabolism of muscle tissue: muscles are broken down so that glucose can be synthesized in the liver from the amino acids contained in them.
Cortisol regulates lipolysis — the breakdown of fats. If the body does not receive enough fats from food, cortisol activates the breakdown of fat reserves to provide energy to the brain and organs.
However, this process is unstable and is accompanied by other hormonal shifts, including increased production of free fatty acids, which can lead to insulin resistance with chronic elevation of cortisol.
Cortisol increases not from the number of meals but from nutrient deficiency. Even if you eat 4–5 times a day, if the diet is predominantly carbohydrates and fats and proteins are deficient, the body does not receive the necessary amino acids and fatty acids. This is perceived as stress, and cortisol begins to perform a compensatory function: "harvesting" the needed elements from the body's tissues.
Consequences of chronically elevated cortisol
- Loss of muscle mass
- Increased anxiety and irritability
- Sleep disturbances (cortisol suppresses melatonin production)
- Insulin resistance
- Accumulation of visceral fat (especially in the abdominal area)
Conclusion
Cortisol is not just a reaction to hunger as a lack of food; it is a reaction to internal deficiency of necessary substances.
Proteins and fats are key macronutrients without which the body perceives the situation as a threat to survival, thus triggering the stress cascade.
Therefore, a balanced diet with sufficient amounts of proteins and fats is one of the main ways to keep cortisol under control.
