To begin eating; to start the action of eating something.
みんなが揃ったら食べ始める。
We will start eating once everyone is here.
彼はコーヒーを飲みながら食べ始めた。
He began eating while drinking his coffee.
子どもは最初は少しぎこちなく食べ始めることが多い。
Children often start eating a bit awkwardly at first.