What is juicing?
Juicing refers to the process by which all the liquid or natural juice from fruit and/or vegetables is extracted.1 This is often achieved by placing fruit and/or vegetables in a juicer, although they can also be squeezed or pressed by hand. Unlike smoothies, the solids are not blended in, resulting in the loss of copious amounts of fiber and nutrients. Juicing can be performed in two ways: centrifugal juicing or cold press juicing, the latter of which is the most popular and preferred method.2 Centrifugal juicing, as the name suggests, involves crushing fruit and vegetables via a sharp metal blade that spins at a very high speed (i.e. centrifugal force). Cold press juicing, on the other hand, crushes and presses fruit and vegetables at a very low speed. Centrifugal juicing, as opposed to cold press juicing generates excessive heat, causing people to claim that cold pressed juices are healthier because the nutrition content of the fruit and vegetables is relatively unaffected. However, this claim has been discredited by a recent study which found no significant difference between the nutritional quality and antioxidant capacity of centrifugal (normal) and cold-pressed juices.2
In addition to cold pressed juices, the most popular juice recipes that are used for cleanses and ‘’detoxes’’ today include green juices and celery juice but also orange juice, pomegranate juice, carrot juice, lemon juice, cucumber juice and watermelon juice.
Is juicing good for weight loss?
There is no scientific evidence available to prove that juicing is good for weight loss. It is true that juicing can contribute to weight loss but that is because juice diets and juice cleanses are very low in calories. Juice diets, juice cleanses, juice ‘’detoxes’’ or juice ‘’fasts’’ encourage individuals to refrain from eating all solid foods and rely exclusively on fruit and/or vegetable juices for a duration lasting from days to weeks.3 Unfortunately, because this is the case, the results are short term, with studies showing that, once juice diets are stopped and people return to their regular eating habits, all the weight is gained back, if not more!3
Is juicing healthy?
The answer to this question depends on multiple factors: how the juice is prepared, the quality and growing conditions of the fruit and vegetables and most importantly, whether juicing is used to supplement or replace a healthy diet. Generally, juicing can be a healthy way to consume more fresh fruit and vegetables, especially if one is a picky eater and despises fruit and/or vegetables (Mayo Clinic).4 Juicing can also be helpful in increasing the overall intake of fluids, nutrients and vitamins especially vitamin C, E, beta carotene (precursor of vitamin A), selenium and folate.5 That being said, juicing should not be used as a replacement for solid food, whole fresh fruits and vegetables or a healthy diet in general. To get more bang out of your buck, consider making smoothies instead of juicing as research studies suggest that the added fibre will not only help you lose weight, if that is your goal, but also stabilise your blood sugar and keep your hunger at bay!6
Benefits of juicing for weight loss
List of benefits
- Juicing can induce weight loss in a short amount of time.3
- Juicing can improve the gut microbiome and thus facilitate weight loss by increasing and decreasing the abundance of weight loss-inducing Bacteroidetes and weight gain-inducing Firmicutes within the gut respectively.7
The right way to juice
If one is very passionate about juicing, juicing should be used to supplement rather than replace a healthy diet. It is worth adding more vegetables than fruit to your juice to prevent huge blood sugar spikes. For example, try adding spinach, kale, parsley, romaine lettuce, cucumber, celery, lemon and apple.7 Another option could be apple, lemon, ginger and beets. It is advised not to discard the solid remains of the pressed fruit and vegetables as they are packed-full of nutrients, vitamins, beneficial plant chemicals and fibre. Why not ‘recycle’ them and add them to soups, dips or stews for a hearty, gut-loving nutritious ‘’boost’’?
The wrong way to juice for weight loss
As discussed previously, juicing should not be used as a food replacement or a way to skip meals and avoid eating. It is also not advised to carry out juice cleanses or juice diets for long periods of time as this might deprive the body of nutrients and protein, the latter of which is essential to increase and maintain muscle mass. Interestingly, people who have higher muscle mass have been demonstrated to have a ‘’faster’’ metabolism and thus ‘’burn’’ more calories at rest compared to those with lower muscle mass.8
Who shouldn’t juice
People who have a history of any type of eating disorder, are very active, have weakened immune systems and/or struggle with fatigue, low energy, diabetes or blood sugar imbalances are advised not to carry out juice cleanses or go on a juice diet. Juicing is likely to do them more harm than good. Before going on any juice cleanse/diet, please speak to your GP or healthcare provider.
Health concerns of juicing (National Center for Complementary and Integrative Health)9
- Juice diets and juice cleanses put individuals at risk of muscle loss, low immunity, nutrient deficiencies as well as weight regain
- Juice cleansing puts the body in ‘starvation mode’ and ‘’slows down’’ metabolism, thus causing individuals to ‘’burn’’ fewer calories at rest whilst holding onto excess fat.10 This defeats the whole purpose of juicing
- Juice diets can contribute to weight management issues due to their restrictive nature
- Juice diets are very low in fibre, protein and healthy fats, all of which aid weight loss by increasing satiety
- Fruit juice, in particular, is very high in sugar and the matter is made worse due to no fibre available to help stabilise blood sugar,6 resulting in huge blood sugar crashes
- Fruit juice, especially when consumed regularly and excessively, can increase one’s risk of developing obesity11
- Juicing can predispose individuals to disordered eating habits and even eating disorders12
- Juicing can increase one’s risk of developing kidney problems because many raw vegetables such as spinach and beets are high in oxalates
- Juicing can cause indigestion and diarrhoea. Over time, these can lead to dehydration and severe electrolyte imbalances
- Juice cleanses can contribute to fatigue, weakness, headaches and even fainting.
- If unpasteurised, juices can put vulnerable people with weak immune systems at risk of serious illnesses
Should you do a juice cleanse for weight loss?
Based on the scientific evidence above, you are probably better off not doing a juice cleanse. The associated health risks certainly outweigh the health benefits. Your mental health, mood, sanity and bank account will likely thank you. If weight loss is your goal, rather than juice cleansing, consider adding more exercise into your routine, limiting your intake of processed foods and eating a healthy calorie restrictive diet.
Summary
Juicing involves the extraction of juice and the removal of fibre, skin, pulp and seeds (solids) from fruit and vegetables. Over the years, juicing has been claimed to ‘’burn’’ belly fat, promote weight loss, ‘‘detox’’ the body from toxins and even help cure diseases such as cancer. None of these claims have been supported by scientific evidence. Juicing can contribute to weight loss but that is not because of any ‘magical’ weight loss property it possesses. Juice diets and juice cleanses are very low in calories so it is only natural for weight loss to occur. Juicing can be beneficial in increasing fluid intake and the consumption of fruit and vegetables. Juicing, however, strips away all the fibre from fruit and vegetables. Fibre is essential for weight loss, satiety and blood sugar regulation.
Furthermore, juicing is unsustainable and dangerous, putting people at risk of developing nutrient deficiencies, muscle loss, low immunity, both blood sugar and electrolyte imbalances, fatigue, diarrhoea, frequent headaches and severe dehydration (to name a few). Paradoxically, juice diets and juice cleanses can also induce rather than prevent weight gain due to their extremely restrictive nature.
In conclusion, juicing offers no special benefits for weight loss and should be used to supplement rather than replace a healthy diet. Juicing can do more harm than good and is therefore not recommended as a long-term weight loss strategy. People with eating disorders, weakened immune systems, are physically active or have health conditions such as diabetes should steer clear from juice cleansing and juice diets. If weight loss is the main goal, one is better off engaging in more physical activity, limiting processed food intake, consuming whole fresh fruit and vegetables (not just the juice but the skin and pulp too!) and/or blending them into smoothies.
References
- Ruxton CHS, Myers M. Fruit Juices: Are They Helpful or Harmful? An Evidence Review. Nutrients. 2021 May 27;13(6):1815. doi: 10.3390/nu13061815.
- Khaksar G, Assatarakul K, Sirikantaramas S. Effect of cold-pressed and normal centrifugal juicing on quality attributes of fresh juices: do cold-pressed juices harbor a superior nutritional quality and antioxidant capacity? Heliyon. 2019 Jun 18;5(6):e01917. doi: 10.1016/j.heliyon.2019.e01917.
- Obert J, Pearlman M, Obert L, Chapin S. Popular Weight Loss Strategies: a Review of Four Weight Loss Techniques. Curr Gastroenterol Rep. 2017 Nov 9;19(12):61. doi: 10.1007/s11894-017-0603-8.
- Mayo Clinic. Is juicing healthier than eating whole fruits or vegetables? [Internet]. [cited 2022 December 27]. Available from: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/juicing/faq-20058020
- Kiefer I, Prock P, Lawrence C, Wise J, Bieger W, Bayer P, Rathmanner T, Kunze M, Rieder A. Supplementation with mixed fruit and vegetable juice concentrates increased serum antioxidants and folate in healthy adults. J Am Coll Nutr. 2004 Jun;23(3):205-11. doi: 10.1080/07315724.2004.10719362.
- Waddell IS, Orfila C. Dietary fiber in the prevention of obesity and obesity-related chronic diseases: From epidemiological evidence to potential molecular mechanisms. Crit Rev Food Sci Nutr. 2022 Apr 26:1-16. doi: 10.1080/10408398.2022.2061909.
- Henning SM, Yang J, Shao P, Lee RP, Huang J, Ly A, Hsu M, Lu QY, Thames G, Heber D, Li Z. Health benefit of vegetable/fruit juice-based diet: Role of microbiome. Sci Rep. 2017 May 19;7(1):2167. doi: 10.1038/s41598-017-02200-6.
- Cava E, Yeat NC, Mittendorfer B. Preserving Healthy Muscle during Weight Loss. Adv Nutr. 2017 May 15;8(3):511-519. doi: 10.3945/an.116.014506.
- National Center for Complementary and Integrative Health. “Detoxes” and “Cleanses”: What You Need To Know. [Internet]. [cited 2022 December 27]. Available from: https://www.nccih.nih.gov/health/detoxes-and-cleanses-what-you-need-to-know
- Müller MJ, Enderle J, Bosy-Westphal A. Changes in Energy Expenditure with Weight Gain and Weight Loss in Humans. Curr Obes Rep. 2016 Dec;5(4):413-423. doi: 10.1007/s13679-016-0237-4.
- Wojcicki JM, Heyman MB. Reducing childhood obesity by eliminating 100% fruit juice. Am J Public Health. 2012 Sep;102(9):1630-3. doi: 10.2105/AJPH.2012.300719.
- Bóna E, Forgács A, Túry F. A léböjtkúrák és az atípusos evészavarok lehetséges kapcsolata. Kvalitatív előtanulmány [Potential relationship between juice cleanse diets and eating disorders. A qualitative pilot study]. Orv Hetil. 2018 Jul;159(28):1153-1157. Hungarian. doi: 10.1556/650.2018.31090.