Puff, puff, puff, puff, puff, puff... walking every day into Oxford along Iffley Road, I'm overtaken by joggers who would be classed as 'anexoric' if they lost an ounce more. They are, of course, usually in their 20s, slim, toned, tanned, and lost in their iPods; so quite why they feel the need to work-out beats me.

Even if they didn't run, chances are their genes would still guarantee a lifetime of fitness and a size '0' wardrobe.

Yet bullishly they persist, pushing their bodies as hard as they can, when Nature itself has clearly blessed them with lifetime cover.

Now thankfully, Oxford boasts some of the most athletic and attractive individuals of any town or city in Europe.

And a flying visit to one of our many gyms proves this point.

Take Esporta, for instance, in Woodstock Road, the highly expensive sports club for people with big cars, bigger watches and still bigger egos.

Hands up, I was once a member and loved it.

But I always stared in wonder at many of its members.

For instance, its women clientele were, and I think probably still are, members of that elite circle of 'ladies who lunch' — that is, wives with husbands who work either in the City or at white collar crime (read: law).

Not one of these women look like they weigh more than a tube of Pringles, but still they pound away, their sweat-proof make-ups perfect and unsmeared.

And the men (in the evenings) are no different — mostly square-jawed types, with muscles you could balance a Hummer on. Yet not once did I ever spot anyone who was actually out-of-shape.

Indeed I wonder if they weren't somehow 'weeded' out during the registration process.

Weight? 18 stone.

Height? Under 5ft.

Favourite meal? Anything 'bucket' size...

Poor swines, they wouldn't stand a chance.

However, when I later joined, for monetary reasons, the council-owned Ferry Sports Centre in Summertown, I saw exactly the same torsos — trim, fit and six-packed — but without the Coutts Bank cheque card.

I guess they were penniless students, most probably at Brookes (Oxford University students would rather gain 10st than workout in anything 'local authority').

Money then clearly isn't the common denominator when it comes to separating the fit from the dead weights.

And if that's so, it means what we should all fear most — that those who least need to take care of themselves always do, and those who really should pass the cream cakes can't be bothered (after all, lifting a platter of fondant fancies and apple turnovers might burn off at least three calories). Initally, this revelation may disturb you, particularly if you're a health professional.

But if you're not, it could ultimately prove to be rather comforting. After all, does anyone who over-eats ever look good in Lycra?

No — indeed when they try it, it's like watching a walrus attempt the 100-metre dash.

And if anything's going to put you off your muesli and Yakult, it's this.

So maybe we should be grateful that those who can't cross bridges — either pedestrian or vehicular — which boast certain 'load' restrictions', choose not to torture us with their flab.

And frankly, that's a weight off my mind.