So, Dr Michael Mosley’s Horizon documentary – Eat, Fast, and Live Longer – was on here in Australia the other week.

Nick and I watched it – and so did my parents.

Independently of each other (even though we live next door!) my parents and Nick and I decided to give it a try.

My parents, as they are both currently living with weight gain that’s been brought on by illness/medication over the last year or two, are keen to try it out to primarily lose that extra weight, but also (as my Dad had cancer last year) to reap the other potential health benefits of the diet.

Nick and I are both at pretty healthy weights, though I would like to lower my body fat percentage – I’d like to get down to an athletic level of body fat prior to next the next Triathlon season, which starts in September for me here in Australia.

So – what is the Fast Diet?

Basically, it’s a form of intermittent fasting.

You eat normally 5 days a week – yep, whatever you want! (Though Nick and I still eat primarily Paleo.) On the 2 ‘fast’ days, you eat 1/4 of your normal calorie/kilojoule intake, which equates to around 600 calories for men and 500 calories for women).

That’s it!! Super-simple.

What does it do for you?

Obviously, eating only a 1/4 of your normal intake of food twice a week is going to help you to lose weight if you need to.

However, the weight loss potential is not why I’m so eager to give this program a try. I am more interested in the potential long-term health benefits to my brain and cardiovascular system, as well as the potential to avoid diabetes and cancer in the long-term. Not that staying slim is a bad by-product, I’ve struggled with my weight like most women!

I took a snap from a page of The Fast Diet book that gives a summary of the potential benefits: 


The science behind the benefits of intermittent fasting is very promising, and I’m going to be keeping an eye on human trials as they happen in future.

It also makes logical sense – after all, throughout most of human history, we did not eat constantly, all day/every day, without experiencing hunger.

Not surprisingly, intermittent fasting in some form is already popular amongst those in the Paleo community, as it does reflect how our ancestors would have eaten more accurately than our 3-6 meal a day Western model.

However! I’ve been hesitant to explore it as an option, because a lot of the anecdotal evidence I’ve read in the Paleo/Primal community has seemed to reflect the fact that it works really well for men, but not so well for women.

After seeing the Horizon documentary, however, the possible benefits indicated by scientific trials were too intriguing to pass up.

You can hear from the man himself in this short radio interview:

And so, here we are – one month for starters, to see how this particular form of intermittent fasting affects me, personally.

{Wonder what these Experiments are about? Read: Experiments Explained}


To eat according to the Fast Diet – the 5:2 Diet – a form of intermittent fasting – for one month.


I hypothesise that this will be a relatively easy eating routine to stick to, and that I will see a drop in overall body fat AND therefore in my body fat percentage (I will be exercising as normal during this time). I hypothesise that I will find it so useful and positive that I will decide to continue eating this way once my month-long experiment is concluded.


  • The internet. Seriously, if you’ve seen the documentary, you don’t really need the book, though it does re-hash the scientific info nicely. I didn’t plan on buying it, but my Mum did, so I stole it and read it 😉
  • If you want it, get the book – The Fast Diet
  • Pin board – collecting 500 calorie meals from around th web.


  1. Fast days on Tuesday and Thursday, were I eat 500 calories split between 2 meals at around 11am and 7pm.
  2. Days are flexible – can be moved if there is an event on, but must be at least 2 days per week, non-consecutive.
  3. Drink as much black coffee, herbal/green tea, and water as I like throughout the day.
  4. Follow this plan for one month. Easy!

Lab Notes

  • My initial measurements are: 

Weight – 71.8kg. (I am 176cm tall – 5’9 – pretty tall for a lady!)

Waist – 75cm.

BMI – 23.2 (I’m not too fussed on this, as I’ve got pretty good muscle mass for a gal)

  • First 2 fast days were very easy. I felt a few hunger pangs, but nothing major. I felt no lack of energy or focus (though on Thursday, I was VERY sick with a cold and had what amounted to a 16-hour work day. And I coped). Boy did I enjoy my food, though! Eating very little in a day helps you to savour your food much more. I also drank copious cups of water, black coffee and green tea.










  1. The Fast Diet