So I’ve just come off the second fast day in my first week on the 5:2 diet and while I can’t say it’s been easy, I feel like I’m starting to get in the groove of it.

The first fast day was tough – I found myself starving at 10am, having had a breakfast of one scrambled egg and one small piece of toast (600kJ). Breakfast is normally my biggest meal of the day so I struggled with the reduced portions.

I decided to do my first fast day on the one day a week I’m in an office (where, like most offive workers, I sit at a computer for most of the day), thinking that my reduced energy needs would make it easier. The rest of the week I’m much more active, on my feet most of the day either running training sessions, working out myself or looking after kids, and I was a little worried about how I’d fare with less food on those days.

But I think I struggled because there was nothing to distract me from my hunger and I thought about food a lot. Drinking coffee and tea got me through to lunch – which I forced myself to wait for until 12pm on the dot – which was vege soup with 40g of chicken. I felt a little like someone from the Depression era as I picked through my soup for every last morsel of chicken and vegetable (beans, cabbage, leek and Brussels sprouts). But the soup was definitely a good option. The whole batch (about a litre) came in at about 330kJ and I had some leftover when I was hungry in the afternoon and after dinner (which was a tiny 60g steak with beans, celery and lettuce). I even had enough spare kilojoules leftover at the end of the day to have a marshmallow (65kJ) and a decaf coffee with a splash of soy milk. Total kilojoules for the day = 1980.

When I woke up early the next morning (with a grumbling tummy) to get in some breakfast before my first training session, I had a slight headache but that went away after eating. Apart from having a second breakfast when I got back from training, I pretty much ate normally for the rest of the day.

My second fast day was not quite as cruisy. I picked a day when I was busier this time because I thought all the running around might keep my mind off food.

Things were travelling pretty smoothly for the first half of the day. I had a coffee around 7am in between training sessions then my (now standard) fast-day breakfast of one egg and a piece of gluten-free toast when I got home around 9.30am.

By 12pm I was again starving despite my later breakfast this time so I made myself a stir-fry with 75g of tofu, beans, celery, a packet of lo-cal noodles (just 88kJ in the whole pack!) and a splash of tamari (515kJ for the whole big bowl).

But then trouble hit. My mum popped over with half a dozen gluten- and dairy-free cakes she’d picked up at the markets! Had it not been a fast day I wouldn’t have thought twice about having one but as much as I tried to show restraint I ended up having a quarter of a chocolate tart that my daughter didn’t finish (OK I also licked the knife!). I thought I’d blown it all right then and there and truthfully, had I not been going out to a fancy dinner the following night I probably would have postponed my fast day and polished off the rest of it! A quick check of the nutritional information on the net revealed my indiscretion had cost me 450kJ. The whole thing came in at a hefty 1800kJ so I’m glad I stuck to a quarter.

I’m starting to get used to weighing and measuring my food, which I haven’t done since I was an obsessive teenager, then writing down everything (and I mean everything) I eat. There’s no room for guesswork when you’re on such a tight caloric budget. As I’ve discovered, there’s also no room for snacking – the odd bite of this or taste of that quickly adds up. So it’s definitely made me more mindful of what I’m eating (no more finishing off the kids’ leftovers – a questionable habit I swore I’d never get into!).

I imagine it also feels a little like what Hollywood starlets and models must go through – obsessing over every last morsel lest it show up on the scales. One thing’s for sure, I know I couldn’t cope with eating like this seven days a week for the rest of my life, trapped in some kind of calorie-counting hell! But I digress…

A light dinner on my second fasting night  (white fish, veges and a spoon of lentils) comes in at 545kJ but the chocolate tart still pushes me over my caloric limit for the day, although in the end it’s only by about 100kJ (25 calories) but I still feel guilty! And I have to admit I’ve worked long and hard to get over feeling guilty about food choices – not a healthy way to live, in my opinion – so this is a double whammy.

But my aim in starting this diet was to see if it was achievable long-term and if it worked so I’ll push on and see what other challenges I face. Unlike Michael Mosley, who presented the recent doco for the BBC and has written a book on intermittent fasting, I didn’t get extensive blood tests before starting. Then again, unlike Mosley, my blood pressure is at the low end of normal, my cholesterol levels are good, as is my blood glucose; I have a BMI of 21 and body fat percentage around the same. So I’m not expecting to see massive changes.

I’m going to base my perception of success on whether I see any changes to my weight, body fat or waist measurement over the next month. Since having a knee operation three months ago I’ve put on about a kilo and my body fat has gone up by a percentage point – not a huge amount in the scheme of things but I can notice the difference – and I know part of the reason is that I’m not as active as I was before my knee injury yet my food intake has remained pretty much the same. So 5:2 might just be the answer I’m looking for. Then again, I might be starving myself two days a week for nothing. We’ll see. Stay tuned…