The term 'diet-friendly' combines 'diet,' from the Greek 'diaita,' meaning 'way of life,' and 'friendly,' from Old English 'freondlic,' meaning 'kind' or 'helpful.'

'Diet' evolved from the Greek 'diaita' to the Latin 'diaeta,' and eventually to the English 'diet.' 'Friendly' evolved from Old English 'freondlic' to the modern English 'friendly.'

Initially, 'diet' referred to a way of life or regimen, but now it often refers to a specific eating plan. 'Friendly' has maintained its meaning of being kind or helpful.