Juice cleanse to gain weight:
Hard-to-measure liquid calories: Since all the calories you’re consuming are liquid, if you’re not watching your intake, it’s easy to consume well over the daily limit. (A pressed juice averages between 100 to 350 calories per 16-ounce bottle.) Make sure you have a plan to follow and an accurate way to determine how many calories are in each glass or bottle you’re drinking. Most retail juicing programs provide calorie counts, but are also pricey to join.
Messes with metabolism: A typical juice cleanse lasts anywhere from three to seven days (or sometimes longer), where you drink 32 to 64 ounces of freshly pressed fruit and vegetable juice each day. When your body doesn’t get the all the nutrients (or the amount of calories) it’s used to, it stresses out because it thinks it’s starving. Often the body reacts to this by slowing down its metabolism, which can make losing weight harder in the future. And while juicing is an easy way to deliver phytonutrients to the body, the fruit-based juices tend to be high in sugar, which can negatively affect insulin levels in the body.
Less exercise: Since you’re consuming less calories than you’re used to (especially in protein, fiber, and fat), many juicing programs encourage conserving your energy by doing less or lower-impact exercise, or even no exercise at all. Less exercise means less calories burned, which may cause extra weight to creep on, especially if you have trouble getting back to the gym after the cleanse ends.
Feeling deprived: Sipping on celery-kale-pear juice might be doable the first day, but you may start to crave all the foods you know you can’t eat. Even if you make it through the entire cleanse without cheating, the feeling of deprivation may be so strong that as soon as the cleanse is over, you can’t help but grab nachos, a burger, fries, and a brownie sundae, consuming more calories in one meal than you normally would have in an entire day before you embarked on the cleanse.