So what’s wrong with the headline: "Eating breakfast can help  you lose weight" The people in the study started eating  breakfast and lost weight— but we don’t know that they lost weight because they started eating breakfast; perhaps having their weight tracked inspired them to change their eating  habits in other ways.
O que há de errado com a manchete: "Café da manhã pode ajudar a perder peso"? As pessoas do estudo tomaram café da manhã e perderam peso, mas não sabemos se eles perderam peso por causa do café da manhã, talvez, ao terem seu peso rastreado, eles ficaram inspirados a mudar seus hábitos alimentares.