We know sleep, exercise and diet are vital for health. But why?

For generations we’ve treated them as separate prescriptions – sleep restores us, exercise strengthens us and food fuels us. Although the brain makes up about 2% of body weight, it uses roughly a fifth of the body’s energy at rest. Exercise doesn’t simply boost muscle mass, it bulks up the hippocampus – a key region of the brain involved in learning and memory. Seen through this lens, sleep, exercise and diet stop looking like three separate pieces of lifestyle advice and become different ways of caring for the same biological inheritance. The reality is that thoughts emerge from living tissue that must constantly capture, transform and use energy simply to exist.