Nutrition Spotlight On: The 5:2 diet

Some of you may have been following my #FastFebruary Twitter updates, and if so you may have noticed I’ve gone pretty quiet for the last few days. That’s because my experiment with the 5:2 diet, or “The Fast Diet“, generically known as intermittent fasting, is now over – and I am enjoying not planning my week around fast days (there is no way I am taking clients on a day when I have not eaten) or weighing every gram of food. I’m enjoying eating regular, balanced snacks and meals, and not worrying about it constantly.

But of course, I owe you all a review, a round-up, and a conclusion.

Fast February

I wasn’t aiming for quantitative data – one person does not constitute a conclusive study and besides, I didn’t have much weight to lose. You can search the internet for testimonials, reports, and even discussion forums on the topic. As for me, my weight fluctuated massively between fast days and non-fast days, and settled at roughly 0.5-1kg lighter than I started, with a drop of about 2% body fat.

My main aim, however, was test how sustainable this diet really was. Of course, everyone’s needs are different so no matter what I found, somebody else would find the total opposite – but I wanted to think about whether this was a diet plan that could or should be recommended by fitness professionals and, if so, to whom?

Somewhere between a crash diet and a balanced lifestyle, the plan has been touted as a sustainable alternative to yo-yo dieting, but I couldn’t help but feel that fasting for two days a week was more up-down stop-start on-off than ever. And yet, it seemed somehow different – namely because it has been publicised on the BBC – and I had no good excuse not to test it.

Weight loss and fat loss

At my lowest weight during the experiment, I had lost 1.8kg. However, my initial weight was taken after a weekend of moderate excess, and the lowest weight was taken after a fast day following a couple of busy days.

So essentially, I didn’t really lose much weight and though I didn’t have much weight to lose, I have been lighter and leaner when taking part in regular and more intense training than I had over the January, so I was surprised that the 5:2 diet didn’t take me to that level.

I did, however, lose about 2% body fat, a more reliable measurement as it relies less on hydration levels, amount of sleep, time of day, and so on. On the other hand, I went from having done hardly any exercise throughout January, to getting back to regular work and training (albeit light!) in February, so the least I’d have expected was a little fat loss around the torso (where I was carrying more than I normally would at the beginning of the experiment).

Now of course, I didn’t have much weight to lose, but surely an effective eating plan would cause almost anyone to drop weight. I do believe all the success stories we read, but it didn’t impress me. I could have lost more weight simply eating a little less overall, cutting back on treats, eating less late at night, and getting out and about a little more, not to mention getting back into some more vigorous cardiovascular training.

Food for thought

This is where it gets interesting for me.

I love food. For some reason, that seems to have become something to be ashamed of these days, but I see no shame in admitting that I enjoy cooking and eating. Food is, and has always been, a social ritual. But sometimes, I get sick of thinking about food all the time, of worrying whether I have enough healthy snacks with me, whether I should eat now or save my appetite, whether I should pick up a treat or go home to make something more wholesome. So I genuinely thought 5:2 would agree with me; indulge in food obsession for a few days, then clear my mind and schedule for other activities for a day.

That wasn’t the case; I obsessed about food more than ever on fast days. Not out of hunger or cravings or boredom, but out of fear – I was scared of being out and getting so hungry and tired that I’d be unable to function, I was scared of being at home and surrounded by food, I was worried about food going off in the fridge without me to cook it. When I did eat, I had to weigh everything, calculate, debate; do I eat this now? Do I wait? How long should I wait?

The day before a fast day, I was surprised at how little I binged but I definitely got a bit anxious late in the evening and felt it was silly to go to bed without having carb-loaded, something I would never normally do before sleep.

The first non-fast day after a fast, I usually ate a lot less than I normally would; a combination of a slightly shrunken stomach, a lack of desire to have anything to do with food preparation, and a busy out-and-about day after a day of lounging around the house being fuzzy-headed.

Guilty pleasures

I did enjoy the feeling of “resetting” my appetite and my eating habits every couple of days, especially if I had eaten a little too much on a non-fast day or indulged in less healthy treats. Unfortunately, I don’t think that’s a healthy attitude to have, and besides, I’m not a fan of anything that implies that we don’t need to take responsibility for our choices. From the first time I heard about 5:2, the assertion that “it doesn’t matter what you eat on non-fast days” irritated me greatly.

This eating plan worries me from the point of view that starvation is addictive, as can be the sense of control over your body and your weight. I have always found it empowering to stand on the scales and see the weight go down, but the flipside is that any increase in weight is accompanied by feelings of guilt. Luckily, I now understand that weight can fluctuate from day to day for a number of reasons – unless you eat and drink and do the same things every day – so I don’t let myself worry. But I can’t imagine everyone would remain quite so cool-headed staring down at a 1kg weight increase after a non-fast day. On the other hand, maybe it’s helpful to witness the daily weight fluctuations so as to destigmatise them. What do you think?


My bottom line is this: I don’t like the 5:2 diet and can’t see many reasons to recommend it to my clients (though I do know some people I think it might work for). I think it works – not for me, but I believe it works and yields results more sustainable than other fad diets – but I don’t think the end justifies the means. Health is about more than weight and fat; health is about happiness, it’s about hormones, it’s about chemicals and atoms far beyond the number flashing on the digital scales or squeezing out from between the calipers. Studies have consistently found that the healthiest, longest-living populations are those with strong social bonds and a vivid sense of community. The 5:2 diet might get you thin, but it won’t help you live longer and it won’t keep your children, or their children healthy.

As always, I have to repeat myself in urging us to forge new, long-term healthy habits and stop looking for quick, superficial fixes. Intermittent fasting may be a more sustainable eating plan than most – if not all – fad diets, but it’s not a sustainable health plan.

That being said, stay tuned for a round-up of my top tips for anyone who has decided the 5:2 diet is right for them…

In the meantime, I’d love for you to share your thoughts and experiences with me!

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