Dylan Dunn’s efforts in 2016 all pointed to him being a star of the future.

The young jockey won Abu Dhabi’s Apprentice World Championship Final, was crowned Melbourne’s best apprentice and even won on a horse owned by Her Majesty Queen Elizabeth II — her first Australian winner.

But just five months into 2017, the 22-year-old has announced his retirement, citing a “never-ending battle” with his weight.

At 178cm, Dunn — the son of famous jockey Dwayne — is far taller than most jockeys and, as a result, he found it extremely difficult to weigh as little as 55kg for some of his rides.

He said that constant ‘wasting’ [a term used in the racing industry to describe losing weight quickly] was the reason he contracted pneumonia on his left lung in 2015 and glandular fever earlier this year — a diagnosis that led to his retirement.

“There were days I just didn’t want to get out of bed because I knew it was going to be a shocking day of wasting,” Dunn told The New Daily.

“The wasting brought on the sickness and the glandular fever … it’s why I’m giving it up.

“I travelled around Australia watching dad, and as a kid I always rode horses. It was my dream [to be a jockey].

“It’s come to an end a lot sooner than I expected — but I probably always knew it was coming because of my size.”

Dunn was initially turned down by Racing Victoria’s apprentice academy because of concerns about how he would manage his weight — a decision that ‘killed’ him at the time.

Determined to make a career of it, he moved to South Australia, got his licence, and, before long, started to rack up winners, leading to a return to Victoria.

Dunn’s life was far from healthy, though, something he now admits in hindsight.

“There’s been weeks where I’ve lost 5kg from Monday to Saturday through limiting food, fluid, sweating,” he said.

“I might have had some lollies every now and then, because I felt like I was going to pass out … it’s bad — a lot of jockeys are anorexic and underweight.

Like father, like son: the Dunn’s share a laugh on track. Photo: Getty

“Sweating in saunas, baths, cars, running in full-length wetsuits — I’ve done it all.

“When driving to the races, I’d put on a plastic sauna suit, ski pants, two skivvies, jackets and then wind the windows up and crank the heat up. I could lose one to two kilos doing that.

“There’s plenty of days you’ll be sitting in the car, 40 degrees (Celsius) outside and it’s so hot in the car. You’re sweating and you feel shocking. About an hour is all I could deal with.

“There’s people who resort to throwing up. I was lucky enough not to do that. That’s another reason why I was willing to walk away.

“I’ve seen what it does to people, who just look sick, and long term, it’s really not good.”

Dunn, who said he “basically completely blacked out” after a race at Caulfield after having to lose four kilograms in one day, also says too much is demanded of many jockeys, citing regular days that begin with track work at 4am and often don’t end until 8pm after a day at the races.

But despite all of this, Dunn — who says he would consider making a return if weight limits were lifted — is far from bitter.

He is an impressive young man who still loves racing, says riding in races against his father was “very cool”, had 133 career winners and can say Queen Elizabeth II knows who he is.

Dunn, who rode her Bold Sniper to victory at Sandown at 19-1 last May, said: “She loves her horse racing and watched the race.

“She wanted to speak to me on the phone but she got [trainer] David Hayes and they spoke about me — that’s pretty cool.”

Dunn will now turn his attention to his mortgage-broking business, Dunn Financial Services, and is expected to work in the racing media.