YESTERDAY, someone offered me a Chewit which I turned down.

It wasn’t because that person was a stranger and it wasn’t because I don’t like Chewits, but it was because I would have to confess to my Fitbit Flex activity tracker that I had it.

With a Fitbit, provided you are honest, there is no more secret eating or cheating yourself that the walk to the car counts as exercise.

And in the interest of honesty, I should say it wasn’t me that declined the Chewit. I wasn’t even offered it, my girlfriend Laura was and she declined it. I relied on her to test the Fitbit Flex on my behalf after I broke an arm falling off my bike (stop laughing).

What she found was that this wrist-worn activity tracker was addictive.

Unlike other wristbands that work out how many calories you have burned and how many steps you have walked, the Fitbit has an interface where you can tell it what food and drink you have had.

It connects wirelessly to your computer and your android or iPhone to tell you how you’re doing and tailors your goals according to how active you want to be and if you want to lose weight.

It rewards you when you meet your goals, but worse is seeing the charts show that you haven’t eaten too much. The technology, as far as Laura was concerned was better than any personal trainer.

Immediately the little snacks were reconsidered and she even took herself for an evening walk to get her steps up one day.

It is water resistant, so she didn’t need to take it off at all and at night time it even tracked her sleep, letting her know how many times she was awoken and for how long.

The Fitbit Flex is available in black and slate for £79.95 from John Lewis. It tracks your steps, calories burned, sleep activity, distance walked and how many active minutes you have had.

Call John Lewis on 08456 049049 or go to johnlewis.com