Jockeys' rooms at racecourses are full of less than tidy sights.Riding tack scattered everywhere, boot polish, teacups, riding gear and small people who look like poorly treated prisoners-of-war.Painfully thin men with sunken cheeks, hollow temples, matchstick-thin arms and legs and every rib capable of being counted.Wearing pantyhose under their jodhpurs because they are lighter than socks and jocks, and a sleeveless mesh vest under racing silks, they lounge around the room hoping their corner

Jockeys' rooms at racecourses are full of less than tidy sights.

Riding tack scattered everywhere, boot polish, teacups, riding gear and small people who look like poorly treated prisoners-of-war.

Painfully thin men with sunken cheeks, hollow temples, matchstick-thin arms and legs and every rib capable of being counted.

Wearing pantyhose under their jodhpurs because they are lighter than socks and jocks, and a sleeveless mesh vest under racing silks, they lounge around the room hoping their corner is the one with the low-calorie air.

When they are riding horses low in the weights, they will use a tiny saddle weighing only a few hundred grams that isn't for sitting on, just something to hang the carbon fibre stirrups off.

And they've been known to revert to all manner of skullduggery to beat the scales.

Some do it more easily than others. They eat a couple of proper meals a week.

Glen Boss, despite being comparatively tall, is one of those that doesn't have too much trouble getting down to about 50kg.

Less than a very small model.

Boss, you would think, is as thin as a human can safely be.

But over the next two weeks he will try and strip three kilograms - the weight of one arm - from a body that has nothing to spare.

Boss has been offered the ride in the WS Cox Plate on Samantha Miss, an emerging champion filly who is one of the favourites in the race regarded as the best on the Australian turf.

And he has promised her trainer and owner that he will be at Moonee Valley on Saturday week weighing less than the 47.5kg she is due to carry.

"I start training today," Boss said after riding Samantha Miss for the first time.

"I'm pretty confident, I feel good at the moment."

But Boss knows he won't be feeling much good by the middle of next week.

"I know what's involved, that's the scary part," he said.

"It's going to hurt a bit."

There are plenty of jockeys who know the feeling.

Most years at this time, the lure of riding a young horse with a chance in the Cox Plate sends a jockey on the sort of spartan mission Boss has embarked on.

Brian York did it a few years ago so he could ride the New Zealand colt Our Maizcay at 48.5kg.

He relied largely on a diet of brown rice, enduring "horrors" to make the weight.

York's horse started equal favourite, but finished last to another three-year-old, Octagonal, who carried the natural lightweight Shane Dye to victory.

Others have to do what Boss is doing every week of the year.

Melbourne's champion rider of three seasons ago, Nick Ryan, has been on a special diet since he was 14.

After he won the jockeys' title as an 18-year-old he grew so fast he went into virtual retirement a year later and is now doing his best to ride at 55kg.

Ask him what he eats and the answer is short: "Nothing."

The great Roy Higgins took much of his nourishment from cigars and champagne and looked forward to the day when he could retire and eat a meat pie.

Wasting, as the practice of severe dieting is known, is hard on the body and can also have devastating mental repercussions.

Fred Archer, the champion English jockey of the Victorian era and a man who stood 1.78m, wasted for all of his adult life.

As a result, he put a pistol to his head soon after riding his fifth Epsom Derby winner in 1886 and was dead at the age of 29.

The science of weight loss has improved since - but it can still be a frightful ordeal, particularly if you have no weight to lose.

Boss will rely on exercise as much as diet.

"It's protein only for the first week," he said.

"No fluids, they're the killers.

"If you need to drink you have a piece of fruit.

"Then you basically don't have a drink for the last five or six days, you don't touch fluids."

For Boss, and those like him, the reward of winning Australia's best horse race is worth the effort.

He justified it as might a man with food on his mind: "It's a big carrot at the end of the rainbow."

Not a bad pot of gold either.