"Juice feast" refers to a period of time where a person consumes only fruit or vegetable juice as their primary source of nutrition. It is a way to cleanse the body, provide essential nutrients, and give the digestive system a break.
I have known people to do juice feasts with Brevilles, blenders, etc, all kinds of juicers, I hope you won't let that be a deterrent, in the film Fat Sick and Nearly Dead they had Brevilles and had great results. (chefambershea.com)