Consumption of protein and carbohydrates reduces cortisol levels through signaling to the hypothalamic-pituitary-adrenal axis.

Study: Characteristics and correlation analysis of postprandial free fatty acids and cortisol levels in males after different meals: a clinical trial

When people ate meals high in protein or sugar, their stress hormone (cortisol) went down over time, which means these foods might help reduce stress in the body.

Study: The Combination of a Diversified Intake of Carbohydrates and Fats and Supplementation of Vitamin D in a Diet Does Not Affect the Levels of Hormones (Testosterone, Estradiol, and Cortisol) in Men Practicing Strength Training for the Duration of 12 Weeks

This study found that eating more carbs (like pasta or rice) lowered a stress hormone called cortisol in men who lifted weights. Even though they also took vitamin D, only the group eating more carbs saw this drop, which supports the idea that carbs help reduce stress hormones.