Juicing is generally safe if you do it for only a few days at a time. However, juice fasts do carry some risks when they are prolonged.
Whole fruits and vegetables are excellent sources of fiber, but that fiber is removed in the juicing process. Fiber is an essential part of a healthy diet. Eating enough of it is important for optimal digestion because it keeps the beneficial bacteria in your gut healthy and may reduce constipation for some people.
Additionally, it may lower your risk of heart disease, diabetes and obesity. By juicing, you significantly reduce your fiber intake, which may result in health consequences.