We know sleep, exercise and diet are vital for health. But why?
The answer may sit inside our cells, a neuroscientist argues. Thinking is astonishingly expensive: the brain is about 2% of body weight but burns roughly a fifth of the body's resting energy, and every memory, decision and idea carries a metabolic cost. Medicine has long treated sleep as restoring us, exercise as strengthening us and food as fuelling us, three separate prescriptions. Emerging neuroscience suggests they are all doing one job: supporting the cellular power plants that descend from a bacterium engulfed by a primitive cell more than two billion years ago.
What it shows: Reported by Guardian (health) and not verified by us: we could not trace this story to a published paper, so treat it as news rather than evidence we have checked.