The X Factor favourite, pictured here on a farm tractor when he was 13, piled on the puppy fat as a youngster thanks to a diet of sausage rolls and Irn-Bru.
But he turned it all around through healthy eating and exercise to become a new heartthrob for teenage girls up and down Britain.
Joe's proud mum Eileen Joyce told the News of the World about her son's amazing transformation - and how he went from singing karaoke at his aunt's house to competing in the country's most popular telly contest.
Eileen, 47, said: "He was a skinny kid until he went into secondary school. He just started living off sausage rolls, chips and fizzy drinks, and then began to get chubby.

"He would absolutely gulp down Irn-Bru, which is packed with sugar. I tried to get him to drink the calorie-free one, but he wouldn't. Instead he would drink about a litre of the full-sugar variety every day.
"All the local shops around his school carried junk food. You could see all his friends were slowly piling on the pounds too. Joe was never bullied about his weight, because it was only a little extra, and all his friends were in the same boat.
"Then one day, about two years ago, he just said, 'I've had enough, I'm going to get fit.' He wanted to feel better - it was never about his career or women."
Determined Joe, who is 5ft 7ins, started running three miles every other day and using his mum's friend's exercise bike. And he started eating vegetables and low-fat meat to get to his current weight of 9st.
Eileen said : "For the most part he sticks to a healthy diet. He does have one vice, though. He loves the sweets Floral Gums.
"I visited him at the X Factor house last week and brought him half a pound because I thought he might be missing them."
Until he moved to London for X Factor, Joe was living with his mum in a two-bedroom flat in South Shields, Tyne and Wear.
She split from his dad, probation officer Jim McElderry, 47, when Joe was a baby. Eileen explained: "Jim and I dated for about a year. We were 27 when we got married - Joe was on the way. We tried to make it work but it just wasn't meant to be.
"Jim and I split amicably when Joe was one. But Joe has a great relationship with his dad. Jim has seen Joe every week for his whole life. One of their favourite things to do together is go to a caravan site in Northumberland."
But for years the family had no idea about Joe's amazing voice - until he tried karaoke four years ago.
Tough
Eileen said: "That was literally the first time we'd heard him sing. My sister has a karaoke machine and she would always have family, friends and neighbours round to give it a go.
"But Joe always refused - he was too shy. Then one day he grabbed the mic and sang Mr Bojangles with his cousin. We were blown away.

"After that his nan convinced him to try out for his school's production of Grease, thinking he could get a supporting role.
"He wound up getting the part of Danny, and the family spent hours taking on the different roles so he could rehearse."
Eileen went on: "I feel like I have watched Joe do a million different performances at school and locally. He was named the Pride of South Tyneside Young Performer of the Year in 2008. It was probably his greatest achievement in life so far, up until now."
And Joe is still the pride of his local community - Colmans fish 'n' chip shop in South Shields has even named a dish after him.
Eileen said: "It's amazing how everyone has gone crazy for him around here. There are posters everywhere. I never imagined this."
But this isn't Joe's first crack at X Factor. He auditioned two years ago as a shy 16-year-old and got to the Boot Camp stage but bottled it.
Eileen said: "I knew he was too young but he was determined. But the day before he was due to perform on boot camp he called and said he wasn't ready. I went to pick him up.
"I was worried the same thing would happen this time. But Joe is ready now. He might seem shy but he's a tough cookie, my Joe.
"He's very strong-minded and moral and would stand his ground if he thought something was wrong.
"He hasn't had one single low point on the show so far."
One of the high points for Joe, says Eileen, is being mentored by Cheryl Cole. "He has always fancied her, since way before he met her," revealed Eileen. "And now he gets to work with her - and not only is she beautiful but she is a lovely person as well.
"She spends loads of time with them and is doing a great job. Last week she was really nervous about her performance but the lads rallied around to her support and she gave them plenty of time as well."
When it comes to other girls, though, Eileen says her son simply doesn't have time for them at the moment.
She explained: "He wanted to be single when he went on the X Factor because he didn't want to have any distractions.
"He's had a few girlfriends - and loads of girls who are friends. There hasn't been anyone serious yet but he's only young.
"As far as I know he doesn't fancy anyone in the house, but his best mates are Rachel Adedeji and Lloyd Daniels.
"Rachel is so sweet - she will come on the phone to tell me how Joe is doing."
"He has been doing so well, and I really believe he could actually win this."
jennifer.wiley@notw.co.uk
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This article has 17 comments
You have an amazing gift Joe, and like Simon said you are a nice person. You deserve all the best, and thank you so much for sharing your talent with the world.
By scot.. Posted March 14 2010 at 1:30 AM.
hey joe, you should let everyone know your secret as to how to get the fat off . sure was a turning point for you mate. your mum sounds like a great person ,look after her you only ever get one mum so both of you enjoy your success . im a great fan of yours at the age of 72 and when your 19 i will be 73 . i was evacuated to southshields during the war after being bombed out 3 times . dont ever lose that gordie accent joe .
By len hudson.. Posted February 17 2010 at 4:05 PM.
We are thrilled that Joe won. His voice is fantastic -
Finally someone wins who deserves it.
Ye must be so proud to have him as a son regardless of whether he won or not - he seems like a really nice guy. Hope all your dreams come true Joe and I hope the xfactor team look after him properly.
By michelle and emma.. Posted December 15 2009 at 7:52 PM.
Joe,i hope-you will be the winner,because your voice really beautiful.You- not screaming-you singing.I`m voting for you.GO JOE!
By Rima.. Posted November 29 2009 at 5:38 PM.
fatty bom bom!
By djbsjkk.. Posted November 29 2009 at 2:40 AM.
I think Joe is a superb singer, great range, great depth and sensitivity - no gimmicks or unnecessary frills. Havent heard a voice with that ability for a very long time and cant wait to buy his first CD. Hope his ability and personality are recognised and rewarded by his winning the show. No one else comes near. Stacey is a good singer, but she hasnt got the range or dependability that Joes voice has and I think its time a lad won, the last two winners have been girls. I think Joe will just get better and better and better. Think he is a superstar to last a long distance and expect Simon to recognise that and all those who vote. All our support from Ireland.
By Brid.. Posted November 27 2009 at 5:38 PM.
joe i know everyone says 'i love you ' but i really love you me and my best friend annabel really wan't you to win hope you
this!!!!!!!!!!!!!!!! JOE McELDERRY 2 WIN 4EVA
ur da best ever
By Sophie.. Posted November 24 2009 at 6:57 PM.
I can only imagine how proud you must be of Joe. The X-Factor is not in America but one day on You Tube I caught Joe's audition and thought he seemed like such a great kid and I thought the family support was extremely moving to watch. Since then I have followed Joe's success, checking his performance each week as well as the results show. You and your family have done a fantastic job shaping Joe into the young man we see perform each week. I cannot believe the transformation from his audition to his brilliant, show stopping performance Don't Let the Sun . . . I forced my wife to come up and watch his performance and it brought her to tears. He has that special ability to connect with different kinds of peole through his singing. I thought Dannii's comments were absolutely perfect and I will pray each night he gets the recognition he has earned and he deserves
By Walker.. Posted November 23 2009 at 6:54 AM.
i love Joe he is awesome Joe to win x factor
By charltte.. Posted November 22 2009 at 1:14 PM.
I love Joe !
His voice is so beautiful it melts my heart. A million, billion times better than anyone else on the show.
GO JOE ! YOU'RE BRILL !
By BREN.. Posted November 22 2009 at 2:10 AM.
I love Joe !
His voice is absolutely beautiful and he ushe win the X
By BREN.. Posted November 22 2009 at 2:09 AM.
I like Joe veryyyyyyyyyyyyyyyyyyy muchhhhhhhhhh, AMAZING!!!
By deedee.. Posted November 21 2009 at 10:12 PM.
I adore Joe, i'm voting for him all the way.
aaaand he is majorly HOT ;)
By neeesh.. Posted November 19 2009 at 9:34 PM.
i love Joe!!=) joe has got 2 win the x factor !! go joe
By tasha.. Posted November 16 2009 at 7:13 PM.
I have been following your journey from your audition to your live shows. Keep it us Joe! I hope you will be the winner of X Factor 2009! Unfortunately, I cant vote for you coz I am from the Philippines! Hope someday you visit our 7,100 islands sharing with us your golden voice as an international professional singer!
By by gerry. Posted Nov. 14 at 11PM.. Posted November 14 2009 at 3:04 PM.
joe to win he is the best male vocal in the compertition not Daniel "Simon" i dunno if their is summat wrong with my TV but joe is the best by far. Joe u missed stevies b day bash so u will have to come back to lowes pad for gud night.
By michael .. Posted November 8 2009 at 1:07 PM.
You are wonderful. Keep going.
By regina.. Posted October 25 2009 at 8:33 AM.