If you wanted to identify the poster boy for sports that used to be prominent and now are mere sideshows, it would be hard to find a better example than boxing.

Once a centerpiece of both American and worldwide sports fans, the roster of current boxing champions and contenders—with a couple of high-profile exceptions—reads not like a Who’s Who, but a who’s that?

Case in point: Audley Harrison, a heavyweight boxer from Harlesden, England,who’s set to tangle tomorrow night on a boxing card in Liverpool in what the British sporting press has dubbed “a big-time bout.” Who is Audley Harrison, you ask?

Exactly.

For the record, Harrison became the first British fighter to win an Olympic gold medal as a superheavyweight at the 2000 Olympics in Sydney, Australia. He’s one of the modern breed of oversized heavyweights, standing 6 foot 5 and weighing 245 (shades of “Big John!”).

After the 2000 Olympics, Harrison turned pro, fought a long string of nobodies and gradually went downhill, eventually losing what was supposed to be a promotional match to an unknown Belfast taxi driver in 2008. But as any boxing fan knows, old fighters never retire, they just keep getting older (and slower), and at the age of 39, Harrison won a televised boxing reality show tournament, went on to capture the European heavyweight title in 2010 and later became the British Commonwealth champion.

Which is a little like being crowned champion of American rugby. Big deal.

Here’s what’s interesting about this otherwise unremarkable match: Harrison’s opponent.

He is one David Price, a 29-year-old, undefeated (13-0) giant of a boxer who stands 6 foot 9 and weighs in at 240 lbs. Along with being younger, taller and ostensibly more talented, Price has racked up a reputation as a bit of outlier in terms of his training techniques.

For example, after finishing 12 rounds of shadow boxing, he plunges himself into a bath of ice cold water, “sitting there for nearly 15 minutes until almost frozen solid,” according to a story in Great Britain’s The Telegraph newspaper.

Along with the ice baths, he has a physical therapist, a sports scientist and a strength and conditioning coach on his training team.

Putting hops in your game

What’s really unique about Price’s training regimen, though, is his diet: He subsists on kangaroo meat. “Mountains of kangaroo meat,” according to the Telegraph Sport.

The results are eye-opening, at least if you believe Mr. Price. After all that ’roo meat, he said that he’s experienced “increased energy levels,” that his hair was growing faster than normal and that his feet had grown in size in a matter of months—all of which he attributed to the nutritional value of kangaroo.

Indeed, as is true of most game meat—venison, bison, elk—kangaroo meat averages only 2% fat and thus is high in protein. Down Under, the meat has long been advocated as a training table staple by track and field athletes, such as pole vaulters, body builders and even triathletes and other endurance sports competitors. According to nutritionists, kangaroo has high concentrations of conjugated linoleic acid, an essential nutrient, and has been touted as having numerous health benefits beyond athletic training, including anti-carcinogenic and anti-diabetic properties.

In Australia, some nutritionists insist that a diet centered on kangaroo meat can help reduce obesity and control atherosclerosis.

Back in Britain, Price has been “munching his way through a mountain of the meat this summer,” according to the newspaper, and his wife Jade, who is a hair stylist, has had to cut his hair every two weeks.

“It has grown so quickly. It’s weird,” Price told the Telegraph Sport. “I’ve even got a big ginger beard which has grown really quickly in the last week. And my foot size was always a 12, but it was 13 when I went for new boots last week.”

Now, kangaroo is hardly going to become a hot new diet food in the USA, and I doubt that most dieters—especially women—would get excited about seeing their shoe size swell by a full number over the summer.

However, it’s refreshing to hear about an accomplished athlete who hasn’t gone vegan (and “feels great!”) or who isn’t gulping down oceans of soy-supplemented protein shakes as the centerpiece of his training diet.

Who knows how much kangaroo meat really contributed to Price’s boxing abilities or his conditioning? Maybe not at all.

But a food product that seems to accelerate the growth of your hair?

Now there’s a market waiting to be tapped.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.