The ‘juicing’ diet, also commonly known as a ‘cleanse’ diet and/or a ‘detox’ diet, is a weight loss diet which has has rapidly grown in popularity over the last 5 years due to an influx of social media advertising and celebrity endorsements. It really is the new health craze.

Juicing is exactly how it sounds. Many varieties of the diet can be run, but all types revolve around the same principle that only fruits, vegetables, herbs and spices can be consumed by the user and they should be in liquid form after being thoroughly blended.

Examples of some drinks users make are:

  • Green Juice (parsley, spinach, pears and celery)
  • Tomato Juice (lettuce, tomato, bell pepper, celery and carrot)
  • Strawberry-Cucumber Juice (strawberries, apples, cucumber, carrots)
  • Blueberry-Cabbage Power Juice (cabbage, apple, cucumber, blueberries)
  • Spinach-Apple Juice (spinach, grapefruit, apples, ginger, celery)
  • Ginger-Beet Juice (orange, kale, beet, ginger, apple, carrot)

No specifics are given to how many shakes can be consumed per day, or the length of the diet, although many juicing diets are advertised as short-term options (1-8 weeks) for ‘rapid weight loss’ and to ‘remove toxins and impurities’ from the body.

The Benefits

  • Easy and convenient way to meet your micronutrient requirements

Micronutrient deficiency is one of the most widespread and dangerous health conditions of the 21st century, and is the root of many chronic health conditions and diseases plaguing the planet. While many people still believe that these deficiencies only occur in 3rd world countries, micronutrient deficiencies are a global pandemic, affecting every nation on the planet.

Even in 1st world countries, 90% of people are deficient in potassium, 80% in vitamin E, 70% in calcium and vitamin D, and 50% in vitamins A, C and magnesium [1][2].

The easiest way to reverse this issue is to dramatically increase the amount of fruits and vegetables in your diet, specifically dark green, leafy vegetables, as they are the most micronutrient-dense foods available.

Further, blending fruit and vegetables reduces the volume of food and condenses it into a compact source of vital nutrients, making it convenient to consume large quantities of nutrients with small amounts of food/liquid.

  • Massive reduction in saturated fat and cholesterol intake

As well as a global issue with micro nutrient deficiencies, we also have a problem with eating certain things in excess, namely saturated fat and cholesterol being near the top of this list. As juicing removes the intake of animal products, and can be seen as a modified-vegan diet, you abstain from the foods contributing the most, if not all, towards saturated fat and cholesterol.

Saturated fat has negative effects on cholesterol levels and the ratio of LDL/HDL, by increasing LDL production rates and reducing LDL clearance rates by suppressing LDL receptor activity [3]. Reducing saturated fat intake also results in a reduction of plasma triglycerides and can reduce the likelihood of cardiovascular disease and strokes.

Saturated fat also has significant effects on impairing insulin sensitivity by reducing adiponectin secretion and damaging insulin signalling pathways required for glucose uptake [4]. In addition, despite recent counter-evidence that dietary cholesterol has no relevance to cholesterol levels and heart disease, this evidence is based on serious methodological fragilities.

The large majority of well-conducted intervention studies show the isolated factor of reducing dietary cholesterol lowers the amount of arterial hardening, restricted blood flow, cholesterol crystallization and arterial build-up of cholesterol [5][6]

  • Rapid weight loss, but only suitable for morbidly obese individuals

Basing your diet around only low-calorie foods such as fruit and vegetables is likely to significantly lower your daily caloric intake. The only exception to this is if one was to revolve most of their shakes around high-sugar fruits such as bananas and apples, and consume a very high number of these shakes per day (~10+).

However, it seems most people who run the diet have ~4-5 shakes per day with ~200-250 calories per shake, resulting in a daily caloric intake of 800-1250kcal.

Such a dramatically low energy intake will cause rapid initial weight loss in even the most sedentary of individuals. However, excess weight loss in a short space of time is likely to result in metabolic complications, fatigue, depression and loss of lean tissue including muscle.

Based on this, the diet is only suitable for those in life-threatening states who need dramatic weight loss for health reasons such as those who are morbidly obese.

The Cons

  • Guaranteed deficiency in dietary protein and fat

 The main issue with juicing diets is they do not include a main source of dietary protein or fat. As protein is required for the structure, function, and regulation of the body’s tissues and organs, a deficiency will cause a loss of lean body tissue, decreased performance, fatigue, metabolic complications, as well as impaired enzyme transcription and regulation of many cellular reactions and processes.

Juicing tends to remove all of one’s main contributors to protein intake such as meat, dairy, legumes, nuts and beans. You must rely on leafy vegetables and fruit for protein, which will be extremely inconvenient and near impossible to reach the 0.8g/kg bodyweight recommendation (unless you chug down pounds of spinach!).

It is strongly recommended to alter the traditional juicing diet slightly by including nuts and a soy-based or pea-based protein powder into your shakes.

The same issue arises for dietary fat, with a lack of fat causing micronutrient deficiency in fat-soluble vitamins, decreased hormone synthesis, and can lead to problems with basic biological functions including growth and development. Including a few fat sources into shakes, such as nuts or coconut, or supplementing with an omega-3 based product whilst ‘cleansing’ is essential to maintain health.

  • Your body doesn’t need a detox/cleanse

The concept of consuming or avoiding specific foods to cleanse or detoxify the body is based upon pseudo-science. In fact, the word “detox” was mentioned by over 300 young UK scientists and engineers to hold no meaning outside of the clinical treatment of drug addiction and poisoning.

Human beings have highly evolved and adaptive biological systems.

The body possesses self-regulatory mechanisms (mainly within the liver and kidney), and a healthy body is more than capable of eliminating the toxic substances imposed on it by the environment or through food. Toxicants within food are not a major health concern, and it is unnecessary for individuals to make drastic dietary changes in fear of toxicity issues.

The Food and Drug Administration (FDA) and other regulatory agencies make use of limits, specifications, action levels and tolerances during food manufacturing to ensure added chemicals or nutrients do not possess the ability to impact human health given highly excessive amounts are not consumed [7].

  • Not sustainable and weight regain is inevitable

You could argue that ‘juicing’ is a valid weight loss method, but for all the wrong reasons. The diet will make an individual lose weight in the same way that starvation will also cause weight loss, which is not a preferable or recommended option. Following the diets recommendations, people could be consuming as low as 800 calories per day. The severe caloric restriction inevitably leads to drastic weight loss, noticed after only a few days.

However, losing weight too fast has been shown to lead to significant losses in lean mass and muscle tissue which could be reduced or avoided by following more conventional, less extreme weight loss methods [8]. In addition, as ‘juicing’ contains little dietary protein, losses in muscle mass will be accentuated even in comparison to a very low caloric diet. The synergistic effect of a low energy intake coupled with little dietary protein is truly a recipe for disaster.

Severely restrictive diets also promote “dieting-induced weight-gain” when people return to normal eating habits. The weight-amplifying effect of extreme dieting is most notably seen in a study on over 2,000 sets of twins, noting twins who embarked on one or more intentional weight loss episodes were significantly heavier than their non-dieting co-twins [9]. Focus on lifestyle changes and implementing a flexible diet that can be slightly altered when your goals change (typically body composition related), such as muscle gain or fat loss.

Who should run the diet?

As previously mentioned, ‘juicing’ is not recommended for anyone outside of morbidly obese individuals who need dramatic weight loss due to being in life-threatening situations. However, if one is willing to alter the diet and include nuts and protein powders in their shakes, then the diet may be suitable for those who want fast weight loss in a short period of time.

 


References

  • https://www.cdc.gov/immpact/micronutrients/
  • https://ods.od.nih.gov/factsheets/list-VitaminsMinerals/
  • Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. (2010). Saturated fat, carbohydrate and cardiovascular disease. American Society for Nutrition
  • Wilcox G. (2005). Insulin and Insulin Resistance. Clin Biochem Rev.
  • Hopkins CM. (1992). Effects of dietary cholesterol on serum cholesterol: a meta-analysis and review. Am J Clin Nutr.
  • Clarke R, Frost C, Collins R, Appleby P, Peto R. (1997). Dietary Lipids and blood cholesterol: quantitative meta-analysis of metabolic ward studies. BMJ
  • Dolan LC et al. (2010). Naturally Occurring Food Toxins, Toxins
  • Most J et al. (2016). Calorie restriction in humans: an update, Elsevier
  • Pietiläinen KH et al. (2012). Does dieting make you fat? A twin study. Int J Obes (Lond)