Lifting the Lid on Fad Diets: The Juice Cleanse.

Lifting the Lid on Fad Diets: The Juice Cleanse.

It’s hard when someone says ‘healthy’ not to think of just fruits and vegetables. Many of us make the mistake of ‘dieting’ exclusively on salads and fruit snacks, when this does not represent a balanced and sustainable diet. Inevitably from this the juice cleanse was born.

What is the Juice Cleanse?

The Juice Cleanse diet was ‘fad’ diet that gained momentum in late 2014 and has been booming ever since. The name accurately describes the majority of ‘meals’ consumed in this short dieting period. The Juice Cleanse works on an on/off basis. In total it can last 11-14 days, including preparation before the diet begins, and aftercare. However, some health bloggers have taken this diet to the extremes dieting over the suggested period.

The rules within the juice cleanse can be very strict. The cleanses tend to contain anywhere between 800kcals-1200kcals for one day. This is a very low amount to sustain a healthy body. Typically, your body requires 1,200kcals alone to survive, e.g respiration, brain function etc. Furthermore, you are not allowed any pasteurized fruit juices, which requires you to buy a juicer or ready-made juices that tend to be expensive. You should commit to the following whilst on the cleanse.

  • 6 juice cleanses a day that are drunk at two hour increments
  • 8 glasses of water
  • Cut out caffeine
  • After the cleanse is complete you should only eating nuts, gluten free grains, fruits and vegetables, water and organic meats/fish
  • Remove all processed, high fat, salt, sugar foods from your diet [1,2].

What are the benefits of the juice cleanse?

The diet claims to help you lose multiple pounds in a very short period of time. Second to that it claims to detox you body (especially the liver) and reset your appetite to favour healthy food.

  • 5-a-day, many of us don’t eat enough fruit and vegetables whereas the juice diet allows us to eat on an average of 9.5 portions of fruit or vegetables.
  • Try more variation, When juicing you may feel more adventurous mixing familiar flavours with ones you are yet to try.
  • It does help you lose weight in the short term. Majority of the weight lost on a juice cleanse is water weight. As we enter starvation mode we use all the glycogen in our muscles as a storage form of energy. With the removal of this comes water. This leads to the appearance of a smaller and thinner body. However, it has been shown to act beneficially to those that suffer from bloating.
  • Vitamin and Mineral Boost, if you aren’t the kind of person that regularly consumes fruits and vegetables, a short stint of shakes can vastly improve nutritional status. This could provide very short bursts of energy and improve your immune system.

What are the drawbacks of the juice cleanse?

  • Raw Food can be ‘dirty’, many raw foods may carry pathogens and is not washed correctly. However, in a traditional diet many foods would be cooked thus destroying bacteria.
  • The diet contains next to no protein. Protein is required in the body to stimulate the growth of new cells and repair old cells. Protein is found in meat, fish, poultry, eggs, dairy products, and legumes. None of which are found in adequate amounts in this diet.
  • It is an expensive diet, Whether you buy the fresh ingredients, juicer, or companies bottled drinks the diet requires a big start up fee and it not for those who are strapped for cash.
  • Diarrhoea, due to the lack of fibre or even any solid food it can lead to diarrhoea and painful abdominal cramping.
  • Low calorie starvation. The diet can consists of very few calories, which leaves the body running on empty. This can create feelings of nausea and dizziness.
  • High Blood Glucose. We all know that fruit is full of sugar, but this usually contained within the cells, called intrinsic sugar. However, when blended and cell structure broken down these sugars are released which means a ‘healthy’ smoothie may contain more sugar than a can of cola. This can send blood glucose levels sky rocketing. This is obviously dangerous for people with poor blood glucose control, e.g Diabetics. However, glucose is the compound our brain uses to measure hunger. If it rises the brain assumes we are full and if it drops it assumes we are hungry. Sugar found in the from that it is within smoothies will be removed from the blood rapidly to be used as a source of energy in the cells. Thus, signalling to the brain that you are hungry. This will increase cravings for more food frequently. Making this diet very difficult to sustain.
  • Inconvenient and poor compliance. Nobody has time to drink every 2 hours, nor do they have the time or patience to make the smoothies and carry 6 around all day! This can lead to poor compliance. Other reasons for poor compliance include its cost, its side effects, its rapid weight loss followed by either slow weight loss or gain, and finally its unbearable hunger.

What are the nutrient deficiencies caused by the juice cleanse?

Vitamin D and Calcium

Vitamin D and Calcium are nutrition’s double act. They work together in perfect harmony to protect the strength of our bones. The role of Vitamin D is to help absorb Calcium so that it available to structurally support the bone. Vitamin D sources include fish, plant oils and fortified margarines. Calcium comes from dairy foods, but also some leafy green vegetables. Although the diet does allow leafy green vegetables they become null and void as there are no permitted Vitamin D sources so Calcium cannot be absorbed.


There are no protein sources permitted during the juice cleanse and are only introduced in the period after the cleanse. This may mean that a person is malnourished of protein for up to 2 weeks. Protein is essential in the body and should make up around 30% of the day's total calorie intake. It is found in foods such as meat, poultry, fish, legumes, nuts and dairy, none of which are allowed before or during the cleanse. This may lead a person to feel weak, and develop aches and pains. No exercise is recommended during the cleanse as there isn’t enough energy (kcals) being consumed to support this. So no excess protein is required for exercise muscle repair.


Recently, the recommended fibre intake has increased to between 24-30g per day. This is due to rise rates of bowel cancer. The act of blending the fruits and vegetables and distinct lack of solid foods means there is little to no fibre in the diet. This can lead to diarrhoea, abdominal cramping and nausea.


Iron is required for blood cell production, division, and energy. Without it a person may feel very weak, fatigued and frequently out of breath. Iron can be found in red meats and legumes, or in vegetables such as broccoli and kale. Although the latter are permitted in the diet, they are less efficiently absorbed due to their non-haem nature.


Zinc deficiency is very common, even in a normal balanced diet. However, in a juice cleanse almost all sources of Zinc are removed. Food sources include shellfish, beef, legumes and seeds. Zinc is essential in the body as it is responsible for DNA synthesis, immune system health, fertility, metabolism of Vitamin A, proteins and carbohydrates and contributes to bone health. During this diet, we recommend taking a Zinc supplement.

Vitamin B12

Vitamin B12 is found in no plant sources naturally. Therefore during an exclusively vegan diet of a fruit/vegetable juice cleanse you will develop a distinct Vitamin B12 deficiency. Vitamin B12 is essential for energy production, cell division, immune and nervous system function. It would be advisable to take a Vitamin B12 supplement during your time on the juice cleanse.

At Oxford Vitality we do not condone or recommend undertaking the juice cleanse diet, however, if you are adamant we ask that you do so carefully and putting your nutrition as your top priority. Consult a doctor before undertaking any drastic diet or if you experience any strange side effects. There is no substitute for a healthy diet and exercise programme for healthy weight loss.

  1. Vallient.M. (2012). Do Juice Cleanses Work? 10 Truths about the Fad. Available:
  2. Urban Remedy. (2016). How to do a Juice Cleanse. Available:
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