Juice diets: Do they work & how?

Juice cleansing has risen in popularity in recent years, hailed as a fashionable way to detox and lose weight.

While there are safe and beneficial ways to juice cleanse, you must understand what you’re doing and why it might be harmful to your health before you start.

What is a juice cleanse?

A juice cleanse means consuming nothing but fruit and vegetable juices to detoxify and lose weight.

The juice can be of fruit, vegetables or a blend of both. Some juice diets demand you drink nothing but juice for a period of time – usually a few days.

Such diets usually promise weight loss in a short time, such as the 3-day juice diet, 5-day juice diet or the 7-day juice diet – or even the ‘7lbs in 7 days super juice diet’.

These are all slight variations on the same thing – forgoing real food in favour of a liquid diet in hope of losing weight quickly.

The 1970’s and 1980’s saw the juice diet go mainstream with the home juicer exploding in popularity with people eagerly extolling the slimming benefits of freshly-pressed juices such as orange juice.

The fact that a 200ml glass of orange juice contains over 17g sugar was seemingly overlooked!

Today, you’re more likely to find kale, ginger or spirulina in your juice than plain orange.

The green juice diet is hugely popular, with ingredients such as chlorophyll, spirulina and algae all common.

To attempt a juice cleanse, you’ll need a juicer. These appliances squeeze all the juice out of fruits and vegetables while leaving the pulp behind, making them different from blenders or food processors.

Some recipes also incorporate superfood powders and supplements to boost mineral intake.

Because this can be very restrictive in terms of food groups, lots of people are sceptical about how healthy juice cleanses are.

How long does a juice cleanse last?

Juice cleanses usually last between 1 and 10 days.

The duration of a cleanse can vary depending on the structure you’re following or however long you choose.

Some require a programme of store-bought juices while others provide recipes for making your own at home.

If you’re going to try a juice cleanse, we recommend no more than a couple of days. You should also consider speaking to your GP for advice before starting.

The potential benefits of a juice cleanse

There are some potential benefits to trying a juice cleanse, although there is little scientific proof to support these claims.

It should come as no surprise that fruits and vegetables are rich in vitamins and minerals.

Drinking juices can make getting a variety of these nutrients into your body simple.1

The high vitamin content of fruits and vegetables can also support the immune system.

Many advocates claim the method’s ability to flush away toxins from the body. However, it’s not clear what these toxins include.²

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The potential risks of a juice cleanse

Juice cleanses are a type of crash diet that deprives your body of lots of the nutrients you’d get from a fully balanced diet.

While there may be benefits to a short cleanse like this, you should also be aware of the possible side effects before you start.

These cleansing diets are usually low in calories, which can mean a temporary weight loss but is unlikely to result in long-lasting change.³

Some juice cleanses also include laxatives or beverages which stimulate bowel movement.

If you lose too many nutrients this way and don’t replenish them, for example through a balanced diet, you’re likely to become dehydrated and suffer from an electrolyte imbalance.⁴

Some more symptoms of these low-calorie diets can include:

• Dizziness
• Fainting
• Headaches
• Fatigue
• Constipation
• Diarrhoea

While fruit and vegetable juices are high in vitamins and minerals, they lack protein which is required to build and maintain muscle.

If you’d like to try a juice cleanse for yourself, we recommend speaking to your GP beforehand to find out what’s best for you.

You might find it’s better to stick to a balanced diet of healthy food and drink, ensuring you get all the nutrients your body needs.

Do juice diets work?

We take a look at the benefits and risks of the juice diet – and how to make juicing work for you.

Can you lose weight by juicing?

Some people can lose weight on a juice diet.

Losing weight on a juice diet is more likely to be down to the small amount of calories you take in while on a juice diet than any fat loss. There’s nothing about juice itself that promotes weight loss.

Even if you initially drop some pounds, they’re more than likely to return after a few days on this diet.

Juice diets are highly restrictive, leading to increased hunger and a lack of satisfaction often resulting in later overeating to compensate.

Studies show restrictive diets actually lead to more weight gain in the long term due to increased cravings and a vicious cycle of dieting and binging.

So, in the short term you will likely lose weight on a juice diet, however, this weight loss is not sustainable and weight regain is common once a normal diet is resumed.

What if I’m on a juice diet long-term?

It’s not advisable. Long-term juice diets can lead to a loss of lean muscle mass due to the lack of protein in juices.

Alongside being an essential nutrient, protein is key for a lean and toned figure, therefore juices are not the way to get the toned body and six-pack of your dreams!

Will a detox juice diet cleanse my body?

The juice cleanse diet idea is a bit of a marketing tool.

Despite the claims, no juice can ‘cleanse’ or ‘detox’ your body.

Our body has a natural detoxing system- the liver and kidney, which naturally detoxes for us. Don’t be fooled by the juice detox diet myths.

Can a juice diet support my metabolism?

Unfortunately, there is no food that can speed up your metabolism and burn fat, including juices.

Despite the fat-burning claims of juices, this is not backed up by scientific research.

Will a juice diet mean I get a full range of vitamins and minerals each day?

Following juice diets long term risks depriving yourself of essential nutrients you need to function such as protein, healthy fats and vitamins & minerals such as B12 and iron.

This can lead to a depleted energy levels, and the fuel your body needs

Juices can be a beneficial add on for individuals who struggle to get in their daily fruits and vegetables, juices can help top up their vitamin and mineral intake.

However, there are many cautions to consider, highlighting why juice diets may not be the best option to reach your goals and sustain weight loss long term.

Will a juice diet give me better gut health?

No. The juice diet could actually be detrimental to gut health.

Fibre is one of the most beneficial nutrients in fruit and vegetables, which is lost in juices.

A lack of fibre is detrimental to our gut bacteria, who thrive off fibre.

Our gut bacteria are essential for our digestive health, weight management, skin, mood and brain functioning, yet a lack of fibre can lead to an imbalance in the positive and negative fibre in our gut.

Stick to whole fruits and veg to ensure sufficient fibre intake.

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Are juice diets too sugary?

Juices can be high in sugar. Although this is natural sugar from fruits, it still has the same metabolic effect on our blood sugar levels as regular table sugar.

Further, you’re likely to consume far more fruit via a juice than you would by eating whole fruits, meaning your sugar intake is drastically increased despite only eating fruit.

Also, when fruit is juiced, the fibre from the plant walls is lost, meaning the sugar has a stronger effect on our blood sugar levels, compared to whole fibre-rich fruit.

What should I do instead to lose weight quickly?

There is no real healthy way to drop weight quickly. If you do end up losing weight using a fad diet, it’s well known that the weight is likely to return as quickly as it disappeared.

A more sustainable method for weight loss is to go for a whole food diet, including fresh fruits and vegetables, healthy fats, protein and complex carbohydrates such as sweet potato and brown rice.

Juices can be added as an extra to top up on your vitamins and minerals.

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So, does juice have a place in a healthy diet?

Absolutely. Try green juices – they’re full of vegetables and leaves such as spinach or kale are much lower in sugar than the fruitier juices.

Think of juices as an add on to meals, rather than a replacement, this way you don’t risk having a restrictive relationship with food or becoming deficient in important nutrients.

Can juice diets be dangerous?

There are certain considerations when starting a highly restrictive, high-sugar diet such as a juice diet. You could experience headaches, loose stools and dizziness.

People with diabetes or hypoglycaemia shouldn’t do a juice diet at all, as juices can cause blood glucose levels to rise dramatically.

Also, juice diets can promote an unhealthy relationship with food. Food is not the enemy – we need plenty of it to nourish our bodies and have the energy to go about our daily lives.

Juicing the right way – our top tips

• Smoothie - spruce up your juices and consider smoothies instead. Not only will they be more textured so you’ll consume them slower, but they’ll contain extra nutrients, too.
• Roughage - add some fibre to your juiced drinks. A pinch of ground flaxseed, a handful of oats or some chia seeds will add essential fibre while having a more satisfying mouth-feel.
• Eat fat to lose fat – add nut butter, oats, avocado, to a smoothie to increase the protein and healthy fats.
• Don’t forget whole food - pair juices with a diet rich in whole foods, healthy fats, proteins and complex carbohydrates for sustainable weight loss that will last long term.

Last updated: 22 September 2021