You are just issued a certificate. At the present time we do many of the same drills but aren't able to get together as often. In with very little or in some cases no training and some of them have done very well. Pro sumotori in Japan only eat two very large meals a day. The center piece of which is a rich stew called chanko nabe.
Amateurs here eat pretty much whatever they want.
Keep in mind that in Japan there are no weight divisions so they want to pack on a lot of weight. In amateur sumo, we have weight divisions, so we don't have to pack on weight unless we want to. I am working on losing weight. There are fewer fifty wrestlers in North America. My club currently has about six.