Measurements show that a resting person has a steady consumption of energy, depending on size, weight and gender. When the person is lying down, completely at rest, with the stomach empty, this quantity is known as the basal metabolism. For a man weighing 70 kg it amounts to about 7000 kJ per 24 h and for a woman weighing 60 kg, it is about 5900 kJ. Under the conditions of basal metabolism nearly all the chemical energy from nutrients is converted into heat.