There are many phrases that make me roll my eyes. ‘Go hard or go home.’ ‘No pain, no gain.’ ‘Hel, I’m pretty sure that’s not drinkable but if you want to take the risk then, I don’t know, go for it I suppose…’

But none is more annoying than this little gem.

‘Just eat a bit less and move a bit more.’

In the UK there’s a nationally sponsored health campaign for which this is pretty much the slogan. (Eat well. Move more. Live longer.) The thing is, on the surface it sounds like the easiest, most practical advice ever. It’s just common sense, right? Everyone can get behind this!

No. It’s damaging and impractical. But let’s unpack precisely why this well-meaning phrase is really so rubbish.

It is incredibly unspecific. It gives you absolutely no goals to work towards or indication of how to achieve what it says. Eat less? Great! How much less? Like, half portions? 600 calories per meal? Eating from a smaller plate? Three raisins a day? What does eat less mean in terms of getting healthy and losing weight, and how on earth do you quantify it? And how about ‘move more’? What does moving mean in this context? Going for a 10 minute walk? Running five miles? How much moving do you have to do and what movement counts?

The reason that most people find it easy to start on diet plans is that that is what they are: plans. Not very workable plans, for the most part, but at least they give you a place to start from and something to aim for. What our annoying little homily assumes is that upon hearing the magic words ‘Just eat a bit less and move a bit more’ a common-sense plan for how to do this will magically form in your brain of its own accord and no measurement will be necessary for its success.

And that’s the main reason this is the world’s worst advice to people looking to be healthier. There is no means of measurement lurking behind this advice. Now, I know I bang on about plans all the time, because I love them. But they really are essential to the accomplishment of a goal.

Without a plan, you’re just pissing in the wind. Sure, maybe the aim of your stream will just so happen to be perfect and you water your mum’s flower bed, but it’s far more likely that you’ll just end up failing and feeling worse (and more covered in wee) than when you started.

It’s true though. You don’t just have to believe me either. Dozens of psychological studies have shown that planning and tracking are essential in the accomplishment of goals. Dr Roy Baumeister, Frances Eppes Professor of Psychology at Florida State University (who wrote an excellent book called Willpower, Rediscovering the Greatest Human Strength) wrote in The Atlantic regarding following through with resolutions:

‘The most important thing is to keep track, day by day, of what you are trying to control.’

This is something that our nemesis ‘Just eat a bit less and move a bit more’ assumes you don’t need to do. And we all know what happens when we jump feet-first into a scheme and find it’s failed. We get really, really discouraged from trying it again.

So, if you really want to help yourself, stop listening when people tell you this. And find a nice simple plan to follow!