A newborn baby needs to be fed every 2-3 hours. They are completely dependent on others for the timing, quantity, and quality of the food they receive.
Later a child learns to get food into their mouth if it’s provided. With time food preferences develop, and we have an increasing control over how much food, what kind of food, and when we eat. Eventually everything about what we eat is our own choice.
Some people take feeding themselves to an even higher level. An elite athlete, for example, pays great attention to every detail of what they eat for the purpose of functioning at their maximum performance capacity. They may have a nutrition coach. Their eating is with a purpose.