In his teaching Jesus says that if they eat his the will live forever and never go hungry or thirsty which initially people were very draw to these ideas. What He meant was that we would live forever with him and heaven and that you will never go hungry in your desire for the presence of God. Once Jesus goes on the say that in order to this you must actually eat His body this is the point that many people get disgusted and confused, which then causes this to be the first time people have ever stopped following him because of one of his teachings. This is important because even though Jesus knew that people would be turned off to this he preached it anyway because it was that important. While thousands of people were turning away from Jesus, He asked his followers if they too were also going to go and while they too did not fully understand they still continued to follow Him because they knew for certain that He was connected with