The juice detox: so is it all just pulp fiction?
Struck down with hypoglycemia two days into a juice cleanse, Kerry Potter investigates if this popular diet trend is harmful or helpful to our health
I wake at 3am, head pounding, dripping in sweat, shaking and itching all over. I know I'm going to be sick, but when I try to walk to the bathroom, I feel faint and lights start flashing in front of my eyes. I crawl instead, vomit and crawl back to bed. My mind is muddled, but one thought makes its way through the fog: am I dying? This goes on for several hours, before I pull myself together enough to lurch downstairs to seek help. Sickness bug? Food poisoning? Worst hangover ever?
No, I'm 48 hours into a juice fast. On each of the past two days, I've drunk four small vegetable and fruit juices and eaten precisely nothing. This equates to a daily calorie content of 400, less than a quarter of my usual intake.
Downstairs, the people running the retreat I'm attending take one look at my grey, frightened face and do a pinprick blood-sugar test on my finger. It reads 3.6 millimoles per litre, which is low; the normal range is between four and eight. I'm experiencing - as a variety of doctors, dietitians and nutritionists later tell me - hypoglycemia.
"A blood-sugar reading under four means you're having a hypo," says UK NHS dietitian Nicky Vernede, who works for Oxford Health Foundation Trust, says. "That should only really happen when you have diabetes. That's low for a normal, healthy person. Two consecutive days of 400 calories is extreme fasting - your body would have been in complete shock."
A couple of the experts I spoke to suggested I might have had a reaction to one of the ingredients in my juices - chia seeds, perhaps - although others thought this unlikely.
Back at the retreat, I return to my room, climb into bed and am given some apple juice and - rejoice! - solids: glucose tablets and crackers with hummus. I take a few cautious sips and nibbles and instantly feel better. My eyelids become heavy and when I awake several hours later, I am human again.
The juice fast may not have agreed with me, but there are a lot of evangelists out there. Of the 15 people on my retreat, I was the only one to react in that way. While I was deranged with hunger for my three-day stay (and no doubt appalling, whiny company), my fellow juicers were uncomplaining. Many were regulars and swore by the regime, returning home pounds lighter, energised, deeply rested and with glowing skin and sparkling eyes.
Converts are everywhere. Department stores have a waiting list for the most popular juicing device, which starts at around €200. Other popular models, running up to €700, are also selling well.
Food is a status symbol like never before, and there's no middle ground when it comes to the obsession with what we put into our mouths. It's either all (I give you the fetishisation of home baking and the ubiquitous cupcake) or nothing (the rise of fast-based diets).
All things in moderation? Not anymore. Gwyneth Paltrow, who never knowingly misses out on a health trend, recently recommended a €4,200 gold-plated juicer on her website Goop.
We live in a world in which there is such a thing as a juicing guru. Step forward Jason Vale, the self-taught, self-styled "UK's leading expert on juicing, health and nutrition", who runs wildly successful juice-cleanse retreats and has sold a staggering three million books. When I'm interviewing celebrities and the conversation turns to their health regimes, a significant proportion name-check Vale in awed tones. He says his own asthma, psoriasis, eczema and hay fever were all kicked into touch when he began juicing.
Fashion types are also mad for it - when I worked on a glossy magazine, colleagues' desks were cluttered with plastic bottles from juice-diet delivery services, while the Instagram feeds of models such as Miranda Kerr and Rosie Huntington-Whiteley show endless images of their breakfast smoothies. Rosemary Ferguson, the model turned nutritionist and naturopath, will publish a book, Juice (Ebury), in April, and does an annual juice fast at a retreat in Turkey.
"The thing I like is that it's not just my body feeling more vital and less sluggish, it's my mind too: I get clarity and perspective. I'm able to cope better with life," she says. When I tell her about my juicing disaster, she says: "Fasts are quite tough, especially your first. But it doesn't have to be that extreme. Adding a juice to your daily diet can only benefit you."
Juicing is now big business
We may currently be experiencing "peak juice", but the practice has been around for decades. In the 1930s, the British-born alternative-health practitioner Norman Walker invented the cold-pressed Norwalk juicer, which is still available.
The Master Cleanse - a prototype juice-fast that involves days spent consuming nothing but lemon juice mixed with water, maple syrup and cayenne pepper - was the brainchild of the naturopath Stanley Burroughs in the 1940s, and is still followed by celebrities today.
In the 1960s, 1970s and 1980s, juicing was seen as the preserve of the hippie health nut, but in recent years it's gone overground, dove-tailing with the trends for fasting and detoxing. In 2010, the Australian filmmaker Joe Cross released a documentary, Fat, Sick and Nearly Dead, which showed him embark on a 60-day juice fast, ditching six stone and a chronic autoimmune disease in the process; a film that eight million people have now watched
Big business has muscled in, with Starbucks acquiring the American juice company Evolution Fresh in 2011, and Coca Cola taking a 90pc share in Innocent smoothies in 2013.
The claims made by juicing proponents are as big as the money involved: these elixirs can purportedly do anything from aiding weight loss and helping skin conditions to curing arthritis and cancer.
What the doctors say
The medical community, however, is less enthusiastic. In fact, every doctor I talked to for this piece snorts in derision at mention of the 'J' word.
Medics, of course, like cold hard facts, and there are no published studies that compare a juice-only diet with other regimes, so the debate is entirely based on personal testimony.
"So many people seem to find some benefit from it and there are so many books about it, you think maybe there is something in it. But everything I know about it suggests it's not a good idea. I've heard the anecdotes, but show me some bloody evidence that it works," Michael Mosley, the doctor and television documentary maker, says.
But hold on, this is the same Michael Mosley who made the 2012 Horizon documentary that offered a compelling, science-based argument for intermittent fasting, before going on to write the bestseller The Fast Diet, a fasting-based eating plan based on the 5:2 model. This involves eating normally five days per week and fasting (well, consuming 500-600 calories) on the other two.
But there's a world of difference between juice fasting and 5:2 fasting, Mosley says. "I'd never recommend juice on a fasting day," he says. "It's about solid food."
The problem with juice fasts, Mosley says, is the lack of protein. "You need protein to fill you up. Unless you have adequate amounts of it, within 24 hours your body starts to cannibalise itself and get protein from your muscles. A juice diet is zero protein, so you will lose a small amount of fat and a large amount of muscle. And if you lose muscle, your metabolic rate will slow down." Which, if you're trying to lose weight, is hardly welcome news.
Fructose: not a 'good' sugar
Then there's the lack of fibre in juice. Dr Robert Lustig is the author of Fat Chance: The Hidden Truth About Sugar, Obesity and Disease and has spent 16 years treating childhood obesity. A vocal anti-sugar campaigner, his lecture on the topic has been viewed five million times on YouTube.
"Eat your fruit and veg, don't drink it," he says. "There are two types of fibre: soluble and insoluble. When you juice, the soluble fibre is still there, but the insoluble fibre is sheared to smithereens by the blades. Consumed together, these two fibres form a gel in your intestine, which limits the rate of absorption of sugar. That's a good thing - it means all the sugar isn't delivered to the liver at once, because when that happens, the liver is going to turn it into fat.
"But when you juice, this gel can't be formed." The result is a spike in blood-sugar levels. "If you look at the blood-sugar rise after eating an apple compared with drinking apple juice, the latter creates a much higher rise," Lustig says.
Fructose - the type of sugar found in fruit and many processed foods - is the big enemy here, according to Lustig's research. Although food manufacturers are allowed to claim its "healthier" than sucrose (table sugar, which is made up of 50pc glucose and 50pc fructose) since it has a lower glycaemic index (GI), pure fructose is more problematic.
Glucose is removed from the bloodstream by insulin, but there's no equivalent hormone for fructose. That job falls solely to the liver, which, if overwhelmed by fructose (say, if you're drinking gallons of juice), can convert it to liver fat. This increases the likelihood of insulin resistance (hello diabetes), furred arteries and heart disease.
The other problem with fructose is that it suppresses leptin, the hormone that tells you when you are full, so you don't know when to stop. Lustig acknowledges there is a big difference between juicing vegetables (which are low in sugar) and fruit, but is unequivocal in his belief that juicing fruit is akin to drinking cola.
This is a view shared by the UK pressure group Action On Sugar, which recently lobbied for the removal of fruit juice from Public Health England's (PHE) recommended five portions of fruit and vegetables per day. PHE's official advice remains unchanged, but it does state that only one portion of the target should come from juice - and a titchy 150ml glass at that.
Juicing "significantly increases your free sugar intake", PHE's chief nutritionist, Dr Alison Tedstone, says. "When fruit and vegetables are juiced, the sugar is released as free sugar, which is the same as added sugar in processed foods."
She also points out the dangers of dental decay from too much juice, as the acid strips tooth enamel - something I've heard anecdotally: a couple of friends gave up juicing because their teeth hurt.
Detoxing: 'people are deluded'
It's hardcore juice cleanses - the ones that last from a day to a week and claim to detoxify your system - that rile the obesity researcher Zoë Harcombe. Medical people hate the 'D' word as much as they hate the 'J' word.
"Detoxing is a nonsense term; it's not a physiological thing," she says. "You can give your liver a bit of a rest by having a few days off alcohol, not smoking, not eating processed food, but it's detoxifying all the time. The idea that giving it juice will help is nonsense. There's a lot of money in the juicing industry - all those retreats and fancy machines. But people are deluded."
That said, some people I spoke to conceded that the odd bit of juicing may be useful. "While I'm not a fan of juice diets, I think it's okay to juice as a supplement to what you eat," Mosley says. "Although, preferably, you want to eat rather than drink vegetables, because eating makes you feel fuller."
Meanwhile, Jason Vale points out that the juices on his fasts are carefully calibrated - for example, they often include avocado to add essential fatty acids to the diet. He emphasises the difference between shop-bought juices (and the pasteurisation process that kills off some nutrients) and freshly extracted juices, and is robust in his defence of juice cleanses.
"When you have hundreds of thousands of testimonials, it goes from being something anecdotal to something you have to pay attention to. There comes a point where everyone can't be wrong. I don't want to have to wait for science and doctors to catch up - just look how long it took them to do that with the dangers of cigarettes."
As for me, the probability of another juice cleanse hovers around zero. I might buy a green juice at Pret A Manger when once I'd have grabbed a Diet Coke, and I do occasionally knock up an apple, kale and cucumber concoction to help face a hangover, since the idea of eating greens with a bacon sandwich seems ridiculous. But whether this makes me healthy or delusional, I'm still not entirely sure.
What the experts say
It's the dietary fad that continues to thrive - but many medics warn against embarking on a juicing programme, brandishing it ineffective, a waste of money, and potentially dangerous.
Sarah Keogh is a dietitian and nutritionist. She runs the Eat Well clinic in Dublin 2, and says that the word "detox" - a term often coupled with juicing - is usually highly misleading.
"The reality is it's a word that has no legal restrictions whatsoever," she says. "You could stick 'detox' on fish and chips if you wanted to."
Although Sarah says that a day or two of juicing is unlikely to cause much harm, problems can arise when people embark on longer plans of five, seven or 10 days.
"Half of all Irish women already don't consume enough iron - and no amount of spinach or kale whizzed into a juice is going to change that," she says.
And another juicing risk flagged by Dr Gillian Smith, who runs The Dental Suite in Bray, is tooth decay and acid erosion. "The worst offenders are oranges, lemons, and limes," she explains.
Dr Gillian says that eating fruit whole is never as harmful as a juice. "If you eat an orange you digest it in your stomach. But stick that orange into a blender and drink it and your teeth take a hammering. You'd need to have 18 pieces of whole fruit to cause the same amount of dental decay as just one juice."
Dr Catherine Barry-Ryan is a senior lecturer in food product development at DIT. "Juice contains a wide range of vitamins and phytochemicals," she says, though she also cautions "home-produced juice spoils rapidly."
Indeed, the US-based Mayo Clinic warns that fresh juices are especially vulnerability to bacteria, especially if they are not kept in a fridge. One 2011 study furthermore confirmed that the likes of salmonella and E.coli can thrive if juicers aren't washed properly.
"Proper cleaning requires hot soapy water and a good scrub," warns Safefood. It adds: "Chopping boards are also guilty culprits when it comes to harbouring bacteria. Cracks and grooves caused by knives can be home to nasty bacteria."
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