2) Avoid any kind of physical activity
Off-season juice fasts should only be performed during a completely active rest phase of your training routine.
“A juice fast done during a more active part of the periodization cycle could actually increase the risk of death or serious adverse events during training, such as cardiac arrest,” Miller says. “There is a risk of severe hypoglycemia from training at too high an intensity on too few calories. The body would just simply run out of fuel.”
While there are cleanses that can last as long as 30 days, three to seven days is the recommended duration.
“At most, you can do one of these cleanses four times a year with three months in between each,” Gidus says. She adds performance will suffer on these types of diets leading to macro and micro nutrient deficiencies, and menstrual dysfunction in women, which leads to calcium and bone loss, increasing the risk for injuries, stress fractures and illnesses.