That isn't all Jesus is talking about, however, with the disciples. In just a few verses Jesus sends them "out, in the boat" and He goes to pray (spend time with God!!) by Himself. THAT is what Jesus is trying to get the disciples to do -- spend time with God to take care of the Spiritual needs of the body as well as the physical. When we are getting so busy we "don't have time to eat" we frequently also "loose" our time with God. Jesus is not only calling US to a 'quiet place' He is showing us how HE took time to stop and be with God.
Is it easy? No! It takes practice, continuing practice -- kind of like the time it takes for the athletes we've been watching compete for spots on the Olympic team. It isn't easy, to compete at that level, either -- but with training, practice and determination the athletes prepare to compete.
It does mean some sacrifice BUT as we spend time with God God will show us the changes we need to make in our schedules so we CAN spend time with God. Training, practice and determination CAN bring us into a closer, stronger relationship with God so we can face our "giants" too.