Why I think the ‘Fast Diet’ gives Intermittent Fasting a bad name

For a few months now I’ve been experimenting with Intermittent Fasting as a fat loss tool. I’ve tried a number of different ways of approaching it – from full 24hrs periods with no food at all, to more regular, shorter 16 hour fasts.

I know that IF is a controversial area with lots of different views on the subject. I’ve read plenty of research that suggests it can be very effective for fat loss and insulin sensitivity. Personally I’ve found it an incredibly effective tool – it’s without a doubt helped my fat loss but also taught me a lot about what real physical hunger feels like. I think that’s a useful thing for anyone on a fat loss mission to experience.

But whenever people find out about my fasting, they always assume that I’m following the Fast Diet. Or the 5:2 Diet as it’s also known. The diet where you eat ‘whatever you want’ for 5 days a week and then eat around 500 calories on the other two.

That approach is not what IF is about for me and I actually think it gives IF a bad name.

I’ll tell you why.



Firstly – for me, IF isn’t a diet. It’s an eating strategy. Another tool in my fat loss toolbox. I don’t need to read a book to know how to do IF and I certainly don’t need a recipe book, because my definition of fasting is ‘not eating’. I choose how long I’m going to fast for and then I don’t eat for that period of time. Simples.

I was astounded to see Pizza Express jumping on the bandwagon promoting a salad that had ~200calories which was ‘perfect for anyone on the 5:2 diet’. I’ll say it again –  when did the definition of fasting change to include eating?

Secondly, the message that you can ‘eat whatever you want’ the rest of the time sits uncomfortably with me. I know that the Fast Diet book is packed with testimonials from people who have succeeded by doing just this. Personally I don’t think an approach which could be interpreted as ‘binge and then starve’ is very healthy. And while the book itself does have subtle hints that you might find yourself wanting to eat healthily, many people have embarked on the 5:2 approach without having read the book at all and I think that’s where the danger lies.

Maybe fasting does allow you to ‘get away’ with eating unhealthy food now and again. But filling yourself full of processed food a few days a week and then trying to fast it off on others isn’t really what IF is about for me. And it’s almost certainly not going to get the best results. My approach is to try eat a healthy, balanced diet with plenty of lean protein and vegetables before and after a fast to make sure that my body gets the nutrients it needs. Yummy as they may be cakes, chocolate and pizza are not what my body needs if I’m then not going to eat for 16hrs or more.

I think the Fast Diet has given IF a bad name, because it’s not really fasting – it’s a calorie restriction diet. And I think that’s a shame as done sensibly alongside a balanced, healthy diet my experience is that IF can be a really effective fat loss tool. But it certainly isn’t ‘a diet’ and for me it definitely doesn’t involve eating!

Of course this is just my opinion and as ever, I’m intrigued to hear from other people with different views or experiences. Are you following the Fast Diet, or doing what I would call ‘proper’ IF? Does it work for you? What’s your approach?

Leave me a comment and let me know.

7 thoughts

  1. That’s interesting. I’ve been thinking about doing some intermittent fasting myself. More as a way of giving my stomach a break every now and again.

    1. John I regularly do 3 to 4 16hr fasts a week. Finish dinner by 7-8pm and then just don’t eat breakfast. Lunch at around midday. It’s pretty straight forward and I’ve definitely seen benefits. Try it out one day and see how you go.

  2. I do like you Becca and do IF about 3-4 days a week. For me it is very much not about counting calories. If I recommend it to anyone I tell them they must read the book first so they understand the principles. It is not about meeting your 500 cals at all. It is about eating enough to stop your body shutting down in starvation mode but not so much so that your body gets enough energy from the food you eat. I follow 5:2 based on the principles in the book. I do dinnertime to dinnertime fasting. If my stomach isn’t rumbling I am doing something wrong.

    1. Wow Dawn – 3 to 4 24hr fasts a week? But you say you still eat something so in a way you’re following the 5:2 approach? I think that’s the main difference for me – when I fast I don’t eat anything at all. Your body doesn’t go into starvation mode during a 24hr period anyway, so you don’t need to eat at all on a fast of that length. But to complete 3 to 4 in a week I can see that you’d probably want to be taking something in to make it manageable. Not sure I could do more than 2 total fasts a week myself.

  3. I’ve been intrigued about Intermittent Fasting since watching the programme last year, so last week I decided to buy the 5:2 diet, and I have the same feelings about it as you do: seems to be a calorie restricted diet more than anything else. Can you explain to me how you approach it? It’s something I really want to give a go, but a 24 hour fast sounds pretty scary, and what puts me off most is fitting exercise around it, any tips?

    1. Sure. I do regular (3-4 times per week) 16 hour fasts. I eat my dinner before 7-8pm and then simply don’t eat until 11-12 the next day. I drink water or green tea for my breakfast and I also workout first thing when fasted. It’s absolutely fine and I’ve never felt wobbly or faint, although perhaps don’t try the exercise until you’ve got a hang of the fasting.

      I find that hunger comes and goes. If I’m busy at work I often find that I forget that I’m fasting until it’s lunchtime and time to eat. It’s really quite straightforward. Just pick a day and give it a go and see how you get on. Let me know!

  4. I have just logged on and was surprised to see your blog as by coincidence my husband mentioned this to me this morning. A couple of people at work have been doing this with good results and I know that one does a lot of cycling (100k rides of a w/e) with no detriment. So I got the book online and read it this morning. I was pleasantly surprised to see that a lot of the research has been done by Michelle Harvey and Tony Howell, who I have worked with in the past and so I know that this is credible work.
    Having just read the book, on the non eating days ‘nothing is forbidden’ so yes you can eat what you like, but the researchers found that in general people self regulated themselves to smaller portions and healthier foods, so effectively they did eat less calories. How else would they lose weight? We all know its a simple sum of input -output of energy and if there’s a positive number at the end you gain weight. The book does emphasise though the importance of long periods with no calories ie 16 hrs to bring about the changes in metabolism and in people’s perception of hunger, fullness and so on. I think the difference is that people have found it possible to sustain this pattern over long periods of time whereas with daily calorie restriction it’s hard to keep it up. It sounds like there are changes in metabolism that are beneficial in terms of losing fat rather than muscle. I’m interested to see that someone who runs regularly has employed this and managed to keep running. I feel encouraged to give it a try,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s