Juice cleanses or fasts are quickly becoming mainstream, boasting a slew of health benefits like glowing skin, reduced digestive issues, and a total body detox, in addition to the obvious rapid weight loss. Traditionally, one embarks on a 3–10 day juice cleanse with the hopes of quickly losing weight. Day(s) long juice cleanses can be daunting and difficult to do, which may be why some people have started replacing just one or two regular meals with a low-calorie, produce packed juice. Consumers feeling pressured to take part in the trend may hope that a green juice a day will provide a slew of health benefits on top of desired weight loss, without embarking on a full blown fast.
Unfortunately, there isn’t much research to back up most claims. One study from 2003 showed that an 8 day juice cleanse lowered blood cholesterol levels in participants, but a week after the cleanse was over, everyone’s cholesterol levels returned to normal (Huber et al., 2003).1 We do know that restrictive diets will lead to short term weight loss, but recent research is now showing us that this weight loss is definitely only short-term at best. The journal Obesity just published a literature review that gathered data from clinical trials studying weight loss in obese and overweight individuals on energy-restricted diets. The authors found that most individuals in the trials were unable to maintain their weight loss, and some participants actually gained back more weight than they started with (Langeveld & DeVries, 2015).
Replacing a meal with juice not only significantly decreases the calorie content, but it also almost eliminates any fat, protein, fiber and sodium—all essential nutrients. Although fresh juices are packed with a wide range of vitamins and minerals, more is not always better. Oxalate, a molecule commonly found in fruits and vegetables, blocks the absorption of important nutrients such as calcium and iron. Oxalates are also dangerous to the kidneys, since they bind to calcium and iron to form crystals, which can become larger kidney stones and block the kidney tubules. Some popular juice ingredients such as spinach, Swiss chard, beets, collards, and parsley are particularly high in oxalates.
Considering that 16oz of fresh pressed juice can contain up to 4lbs of produce, drinking a juice that is high in oxalates every day may do much more damage than good. Restricting calories at one meal may also lead to more snacking or overeating at other meal times, in addition to fatigue and anxiety, common side effects of consuming too few calories or a low blood sugar.
Juices are a great way to supplement your diet, but you should not rely on them to fuel your body as you would normally with food. Just like with your meals, aim for a variety of ingredients—go for a green juice one day and try a beet or fruit juice another day. There is no reason to stop juicing (unless you have certain health problems), and adding fresh pressed juices to your diet may help kickstart a healthy eating plan, but don’t forget to give your body the adequate nutrients and calories it needs to function properly.
1. Huber R, Nauck M, Ludtke R, Scharnagl H. Effects of one week juice fasting on lipid metabolism: a cohort study in healthy subjects. Forschende Komplementarmedizin und klassische Naturheilkunde = Research in complementary and natural classical medicine. Feb 2003;10(1):7-10.
2. Langeveld M, DeVries JH. The long-term effect of energy restricted diets for treating obesity. Obesity (Silver Spring, Md.). Aug 2015;23(8):1529-1538.