It’s just over a year since I started life on the 5:2 or fast diet, made famous by The fast diet: the secret of intermittent fasting – lose weight, stay healthy, live longer by Michael Mosley and Mimi Spencer so it feels time to blog on it. Whilst on leave last August I decided it was time to try something new to lose weight. I’d done various things before that had been successful – most notably running three or four times a week a few years back – but I knew it wasn’t a realistic moment to start running that much again, and yet life was calm enough after moving house to try a new food regime.

This is definitely a lifestyle rather than a diet. For those of you who may have missed the phenomenon (living in a cave for the last year or so perhaps) it’s based on the premise that for five days a week you eat normally and for two days a week you ‘fast’. What attracted me to read the book was reading about the health benefits attached to living like this. Far from being a faddy diet that is actually unhealthy and unsustainable, this is based on principles of fasting that we have known through history and a variety of cultures can be hugely beneficial.

The book only took a couple of hours to read and it really has changed my life for the better, and that’s not something you can say very often about an activity that takes only a couple of hours. It’s so simple that it’s been very easy to put into practice. The first thing to note is that ‘eat normally’ means 2000 calories a day for a woman. When I have plateaued at times in the last year it’s because I’ve been going to town on the five days and eating far more than that.

The two fast days actually involve eating 500 calories. For me that usually means 100 in the morning for breakfast – some strawberries or a boiled egg and spinach for example - and 400 calories in the evening. As a vegetarian it’s probably been easier to find a way of doing this that doesn’t leave you feeling starving. Soup is perfect, or avoiding carbs on these days, eating a big salad with cheese or having lots of veggies so that it’s really easy to feel really full. Then saving 50 calories for a low calorie ice lolly or hot chocolate before going to bed is perfect if you have a sweet tooth like me.

The great thing is that however hungry you feel it’s only ever for just a day. You can think about all the things you’ll eat tomorrow, but when tomorrow comes you find you just want to eat normally. It only works if you have the right things in your fridge at home before a fast day comes, and it’s harder to do if you’re working from home, have a cold, or are flying somewhere, but even then I’ve managed to stick to it. If you slip up occasionally its fine – just start again as planned the following day.

I don’t know how much weight I’ve lost, but I don’t need to know. I am wearing clothes that haven’t fitted me for four years, and for me, not standing on the scales at all since I started over a year ago has been one of the keys to success. I know when I’ve weighed myself in the past that however much weight I have lost, just the act of weighing myself can have adverse effects on my behaviour. If I’ve lost a lot I tend to slack off, if I haven’t lost much I think ‘what’s the point?’ and give up. Once you’ve done the 5:2 for a month or so you’re in the great place of both not having to calorie count – you know instinctively what to eat to feel full – or to be in the tyranny of regularly weighing yourself.

It’s a very short but very powerful book. There is indeed a reason that everyone is (still) talking about it.