Juicehacker Day 1: Why I Am Going On A Juice Fast

Juicehacker Day 1: Why I Am Going On A Juice Fast

Hello, I’m Mark Serrels and for the next week I’m going on a juice fast. My goal is to go from roughly 70kgs to my fighting weight of 65kgs in seven days. It’s a bit extreme, it’s a bit silly, but hey — it might be entertaining! Over the coming days I’l be writing about the experience here at Lifehacker. There will be hunger. There will be tears. There will be juice.

Now that I think about it, this whole thing is all Seb’s fault.

Seb and I started climbing around the same time. Seb had a beard. Seb was super friendly. Seb was a great guy. In a gym full of young human beings with barely a kilo of body fat between them, we had a lot in common: we were both a bit older, both got into this climbing thing in our late 20s. We both wanted to get better. Get stronger.

Now I wouldn’t describe Seb as ‘fat’, but — that inevitable but – Seb was carrying a few spare kilos. He weighed about 80 kilos and I was packing about 73. We trained together, we blasted through campus board work together, did pull ups (dear God the pull-ups) and all the other strange exercises that people who want to climb strong engage in.

Back then I always remember being a step ahead of Seb in the power department. I always kept myself in good shape, even before climbing. I was lighter; my strength-weight ratio was more favourable. I was better at pull ups, had powerful fingers. We climbed at roughly the same grade, but I had more strength.

Then there was that time when I didn’t see Seb for a couple of weeks. ‘He must be climbing on different days,’ I thought.

‘Hey Mark.’

(Another friend. Same gym.)


‘Have you seen Seb recently?’


(Weird, haven’t seen him in a while now that you mention it)

‘I saw him the other day man, you won’t recognise him.’

(Huh? What could they mean?)

Then I saw Seb.

The first thing I noticed is that he’d shaved off his beard. I laughed out loud in the way you always do when a male friend makes a massive change to their appearance.

The second thing I noticed: there was a lot less Seb. A lot less.

In the two weeks since I had last seen him, Seb told me, he had lost an incredible 10 kgs. He literally looked like a different human being. During the last two weeks, Seb had gone on a juice diet. He didn’t eat a single thing. He just drank different types of juice: juice with vegetables, juice with fruit. All different kinds of juice.

Seb was 10kgs lighter and, instantly, he had become a complete machine.

Seb was always heavier than me, but we climbed at roughly the same level. This was because Seb always worked on his technique. He recognised he was a little heavier than most so worked hard on being a precise, efficient climber where I would just blunder my way through the same routes and rely on my power.

But now I had a problem: Seb was stronger than me. Seb was lighter than me. On all possible levels Seb was simply better than me. Since then I swore I would do two things to try and catch back up to Seb. I would work really hard on improving my technique.

And I would go on a juice diet.

Now I’m in the car and my boot is packed full of food: 50 apples, 40 cucumbers, 30 tomatoes, 20 lemons, 4 limes (bizarrely). Mounds of grapes, piles of spinach, kale, celery. For the past hour I’ve been pushing a trolley around Homebush Markets in an attempt to purchase an insane amount of fruit and vegetables and I have been successful. Through the course of the coming week I will shove every item of produce into my newly-acquired juicer and I will drink the absolute shit out of it.

People say that’s silly. People tell me this is unhealthy, I’ll have bad breath, my stomach won’t handle it, I won’t get enough nutrients. Apparently I’ll lose muscle, I’ll put any weight I lose back on immediately. But here’s where I’m at: I like trying weird things. I like doing weird things to my body just to see what happens. I like prodding and tweaking at this biological lump of flesh I have at my disposal. Why not? YOLO, etc.

I’m not overweight and sorta kinda look good naked if I wasn’t so pale. My motivation for doing this is not health, it’s plain old fashioned competition, not just with my good friend Seb, but with myself. I weighed myself this morning before going to work. I’m currently 69kg and my ideal climbing weight is around 65kg (I’m a little on the small side at 5’9″). It’s taken me a year to get from 73 to a steady 68-70 and I’ve struggled ever since. This is an attempt to shed those final kilos and get to my optimum fighting weight, but it’s also another chance to test my resolve with something a little silly and pointless — and I never like to pass up the opportunity to do something stupid.

Screw you Seb, this is all your fault!


  • I think this is great! Considering doing it myself but less extreme, still eating just not as much 🙂

    Check out The Whole Pantry app for some awesome recipes by the way! Sure it’ll help 🙂

    Good luck!

    • Fat, Sick and nearly Dead is a great doco on Joe Cross’ midlife crisis of running to America to live on juice for 60 days.

      I suggest watching it (you can see the whole film on Youtube) as it could inspire you to keep going if you have some doubts about it, and would be good to see what results you might be expecting.

      I got into the juice thing but backed off for a while because I found it very hard to only have juice. My stomach always felt empty regardless of how much juice I had.

      I’m just about to get into a 10 day one this week (or when mum comes home with the organic stuff) and give it another go. I will however look at having 1 simple meal a day. Like a breast of chicken.

      If you decide to go for it then good luck. Invest in a cheap juicer first in case you don’t like it. The slow juicers are what you want but they can be pricey.

      • Thanks! I’ll be sure to check it out.
        What if you had a paleo meal once a day? Could be one of the better options. 🙂

  • Its not a fast to drink juice..

    I have done this before and found it quite useless, given the weight you lose is (as gross as it may be), basically because you’re not full of shit at that point..

    As soon as you start eating, it will gradually regain and you’re just guilting yourself since you will take it as “oh crap look how much weight i’m gaining I must really need to diet!”

    Health initiatives really need to be about health, not about making one number look more like another number you’re told is ‘ideal’.

    • I agree with you about the number thing, but I am healthy and I eat healthy. I just want less weight to carry up the climbing wall. 🙂

      • Ironically the idea is that as you exercise, you will at first lose weight through excess body fat, however will rapidly start actually gaining weight in muscle..

        do you think that weight will make it harder to get up the wall? Ofcourse not.

        the only way this will realistically help is a) 3 days into your clense (not fast), and b) if you keep your energy intake identical to what you need, and in efficient formats (vegan essentially).

        • That’s just not true. Sure I’ll lose a bit of muscle (80% fat/ 20% muscle probably, but maybe more either way) but unless you climb regularly you don’t know just how much a couple of lost kilos can improve performance. I do this all the time when I train with a weight vest. I try routes I can easily do with a 5kg weight vest and all of a sudden there are moves I simply cannot make.

          I lost 2kgs on a break from climbing and immediately noticed the difference. Like a measurable big difference. Of course juicing is no competition for long term healthy eating, exercise, etc, but I already do all of that. This is just a push start thing for me to get me over the line. I’m doing it for a week, not a month, so I think it’s all workable.

          • Doubt you’ll lose that % of muscle you state. A severe caloric deficit is required before youre body starts those shenanigans.
            I share a desk at the office with a heavyset Welsh guy who tried this same program for 2 weeks. He lost a full 8 kgs over the 2 weeks. It has been less than a month since then and he has put it all back on plus 1 or 2 extra simply by going back to what he was doing.
            But you have already stated, most of the weight is just what has been lingering in your stomach and intestinal tract.

          • I’m hoping that, because I have fairly healthy eating habits as it is, I’ll keep it off, but yeah. I get that it’ll be tough.

          • It really all depends on the calories in the juice and how much of a deficit you put yourself into. The higher the deficit the more muscle mass lost and the higher the likelihood of regaining the weight afterwards (metabolic rate decreases after a couple of days of caloric deficit, which is why a large amount of people that lose weight put it back on afterwards, plus extra. It’s a rebound effect).

            Also watch out for the mental effects that come from drastically reducing caloric intake. It’s no coincidence that disordered eating is on the rise and frequently occurs in people that lose large amounts of weight (I’m speaking from personal experience here). Google Minnesota Starvation Experiment for some interesting reading.

            In case you can’t tell, I’m not a huge fan of these diets 🙂 There’s ways to go about this that might be slower, but infinitely better for your physical and mental health.

          • … A weight vest is a different thing entirely. The point is, muscle weighs (for a laymans calculation) about 2.5 times more than fat. Sure, you might start gaining weight – but.. It’s muscle that will HELP you lift, not fat which will make it harder..

            You could look at it like (once the initial fat burn is over), for every X grams of muscle I gain, I can lift X grams more in ADDITION to the weight of the muscle with no huge exertion required.

            I doubt you’d find a body builder who complains his own body is now too hard to lift because of all the weight they’ve gained..

            PS: These aren’t just my goofball theories either – these are fairly well regarded principles..

    • Completely agree.
      Juice has more calories per gram and less fibre than whatever you juiced to make it.
      Plus insoluble fibre (the bit you throw away when making juice) is good for you, having weight loss benefits of making you feel fuller and helping you deal with sugars in a more healthy way.
      I walk the talk too, I have lost 5 kilos and significantly increased my strength, endurance, and fitness at the same time. I exercise a lot, and from a dietary perspective eat more vegetables, no juice, no sugar, same amount of protein, slightly less carbs.
      If you are using the climbing wall as a benchmark, I have close to doubled my speed.

      • Good stuff!

        I’m really good at getting the weight off personally but once I reach my goal (nothing to do with weight, more to do with being able to do the workout scheme I set (which is very varied) every day without any difficulty at the same difficulty, and about how I feel.

        Unfortunately at that point I always go ‘oh good that’s a job well done.. Time for a cheeseburger’ 😛

  • Good luck, Mark! I like these crazy challenges you do!

    Also, it looks like your fridge is overgrown with post apocalyptic urban decay-like vegetation!

  • My Mum loaned me the ‘Fat, Sick, and Nearly Dead’ DVD just for my interest as a Nutrition Science graduate.

    My first instinct with these types of things is to point out all the flaws and rip it apart but at the end of the day it’s a mistake to make ‘perfect the enemy of good’.

    It’s never going to be my first suggestion but I’m not going to rip someone apart for trying it IF they have a well reasoned justification for doing so and it matches their goals.

  • Hey Mark are you keeping a food/juice diary during this time? In particular calories in and calorie expenditure throughout the day.

  • You should try the Ketogenic diet. It helped me lose over 15kgs in just 2 months and the best thing is it’s stayed it off… I god I sound like a commercial

  • Hey Mark, can you add your height to the article so we can get some context on these weights you’re posting please? Looking forward to reading about your journey this week.

    • Oh, I never even thought of that. Will do. And for your reference I’m between 5 “8 – 5 “9.

      • Why is it that we sit back and laugh at American’s and their silly imperial system, but still persist with it for heights and weights of babies?

  • Isn’t 65kg erring on the unhealthily thin side for a grown man? I got down around that low once when I was going through some depressive stuff and I was all sticking out ribs and joint aches and cold.

  • I thought the answer to the question in the title was that you saw an infomercial for that thing that turns everything into soup/juice/smoothies.

  • People tell me this is unhealthy, I’ll have bad breath, my stomach won’t handle it, I won’t get enough nutrients. Apparently I’ll lose muscle, I’ll put any weight I lose back on immediately.

    You forgot to mention that the amount of sugar in juice (especially fruit juice) won’t go down too well either. A glass of juice has about as much sugar as a glass of coke. Depending on how long you keep it up for your teeth definitely won’t like it.

    On the plus side you’ll have plenty of energy.

    • Agree, however most of the juices people “fast” on, predominantly contain: Carrots, celery, green apples (far less frutctose than red apples), cucumbers, beetroot, ginger etc.

      While an apple juice or orange juice is high in sugar, these kind of juices, not so much.

  • Grabbed a Hurom juice press a few weeks back – wonderful machine.

    Tucked into the Beetroot, cale, cellery and ginger juices for about 2 weeks. Had to stop because I was so cleaned out that the juice was going through me in less than an hour.

    Didn’t even lose any weight.

  • Intrigued to see how you go with this, any chance you could post your juice recipes? Are you drinking the same juice for every meal, or mixing it up?

  • I’m in a vaguely similar position, but I don’t think i’m willing to go to the extremes that you are to achieve the end result. I’m a pretty keen runner and as i’m training for my first marathon i’d like to get down to a ‘fighting weight’ so to speak. As my mileage has increased (to around 100km/week) I have dropped some weight, down from 78-79kg June 2012 to 70-71kg now, but i’d ideally like to lose another few. Despite my mileage being consistently high the last bit just won’t budge.

    If I can be stricter on the little things I can probably get it off, but I dunno, eating nothing but juice seems crazy. I’m curious to see how you go (much like I was with the sleep thing), but it’s not something I could stomach myself.

  • Why not just eat the veggies and get all the fibre?

    All juicing does is condense the calories of the food.

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