The method utilizing hot air heating system and a fan of a cooking device i.e. convection steamer, for cooking food i.e. meat. The air heating system and the fan is activated and synchronously pulsated with a pause time of 3 minutes during cooking of the food. The pulsation is regulated by a technically regulated hysteresis of 20 percent of target-cooking chamber temperature. A power supply is stopped and energy supply is reduced during pause time, and a set temperature is maintained in a cooking chamber. An independent claim is also included for a convection steamer for cooking food.