Scottish Male Slimmer of the Year David Cochrane
But as each found themselves confronted by worrying health challenges, this trio of "fatboy slims" finally found the willpower to swap the chip shop for the fruit and veg counter and shed a staggering total of 23 stones between them.
They are among an increasing number of men to join the typically-female environment of slimming clubs.
Now their achievement has been recognised by the slimming group that guided them through it all at a national award ceremony.
Cancer survivor David Cochrane - who battled the bulge at the same time as he fought cancer - has just been named Scottish Slimmers' Male Slimmer of the Year.
Among the runners-up is East Lothian biker Tam Powell, whose diet was kick-started when he realised his thighs were too big to straddle his bike and rest his feet on the ground. In just 18 months, he lost nearly 11-and-a-half stones.
Joining him is Andrew Neill from West Lothian, whose eating spiralled out of control as he grieved for his mother. . He lost more than five stones.
For each of them, losing weight was about more than simply dropping a clothes size.
As they reveal, their battle was also a fight for their lives . . .
DAVID COCHRANE, 35, an accountant from Liberton
Height: 5ft 11ins
Before: 20 stones, 7lb Now: 15 stones, 6lb
TOTAL WEIGHT LOSS: 5 stones, 1lb
When David Cochrane was given the devastating news that the cancer he thought he'd beat had returned, battling the bulge might have been the last thing on his mind.
He'd already lost five stones in just a few months. Now, as doctors confirmed cancer had reappeared in his lymph nodes, counting calories would surely take second place to fighting for his life?
In fact David says the news actually made him even more determined than ever.
Today he's not only fighting back against the devastating illness, but beating his weight down even further.
He was originally diagnosed with testicular cancer more than four years ago.
After surgery, he was put on a programme of regular scans, checks and follow-up monitoring. Just weeks from ending treatment, one of his final scans revealed worrying signs that the cancer had reappeared.
It was a devastating blow,as he'd worked hard to improve his health on the Scottish Slimmers plan, losing five stones in just six months.
"I'd been told my blood pressure was up and I didn't want to go on medication," he recalls. "My wife had lost three stones on the Scottish Slimmers plan, so she encouraged me to try it.
"I didn't go to classes, I did it all online and it was amazing."
His lifestyle was better than ever. In fact, David and wife Lucy, 31, had just returned from a series of gruelling hillwalking holidays when news that he had to start a nine-week course of chemotherapy left him reeling.
"It affected my appetite and I ended up starting to put back weight on," he adds. "I'd worked hard to lose five stones - I didn't want it back on.
"But the chemotherapy affected my taste and I was craving all the wrong kinds of things. I put on a little bit, but then I stuck to the plan and it came back off.
"If anything, going through the treatment made me all the more determined to stick to the plan for my health's sake."
Now, he says, the title of Slimmer of the Year is further encouragement to keep battling the bulge.
"I've changed my lifestyle completely," he adds. "I'd recommend it to anyone."
ANDREW NEILL, 32, of Kirknewton, a pensions administrator at Standard Life
Before: 21 stone, 1lb
Now: 16 stone, 5lb
TOTAL WEIGHT LOSS: 5 stone 1lb
Andrew Neill piled on the pounds as a teenager, when the paper round he'd started to help him lose weight took him on a calorie collision course - straight past the local chippy.
By the time he was 19, he tipped the scales at 19 stones.
And though he had tried to diet in the past, it took the heartbreaking loss of his mum to finally force him into doing something about it.
"My mum, Myra, was 56 when she died from leukaemia in January last year," says Andrew. "I spent most of that year eating or drinking my way through grief.
"It came to a head last New Year. I drank my way through it, woke up on January 2 and saw myself in the mirror.
"Quite frankly, I was disgusted."
Years earlier he'd joined his mum at a Scottish Slimmers class and knew what to expect.
Within days he'd plucked up the courage to return and instantly the pounds began to melt away.
"I was shocked my weight had got to 21 stones," he recalls. "I knew this time I had to stick to it."
He ditched the chip shop visits and his favourite work snack - chocolate bars from a vending machine - and embarked on a new healthy eating plan that he says kept him full and still allowed him to indulge in regular treats.
As he lost the weight, his confidence grew. He even found himself a girlfriend.
"It can be daunting at first walking into a slimming club, but you quickly realise that everyone's there for the same reason," he says."I feel so much better now.
"I play football twice a week and I play squash and I take pleasure in preparing my own food and planning what I'm going to eat.
"Everything is so much easier now the belly has gone!"
TAM POWELL, 64, is a boarding kennel owner from East Lothian
Height: 5ft 5ins
Before: 23 stone, 3lb
Now: 11 stone, 10.5lb
TOTAL WEIGHT LOSS: 11 stone, 6.5lb
As the boss of a busy boarding kennel, Tam Powell needed to be fit enough to cope with handling the demands of his four-legged guests.
But as his weight rocketed, he found it harder and harder. "I was eating junk food all day, I never had a proper meal - it was all fish and chips and black pudding or pie suppers," says Tam, of Longniddry.
"I was at the stage where I'd even catch a taxi to and from the shops because I couldn't walk.
"The final straw came when I got on a plane and couldn't do up the seatbelt.
"I tried to hide it but a steward noticed and the plane had to be delayed while they found an extension for the belt. I was horrified."
His love of motorcycling had also gone on hold.
"My legs were so fat that I couldn't sit on the bike and touch the ground with my feet," he admits. "I was 'kaput'."
He joined his local Prestonpans Scottish Slimmers class nearly 18 months ago, swapped his fry-ups for porridge and fish suppers for healthy grilled chicken, fish and pork.
"I realised my portions were far too big. Writing down everything I ate made me realise how much I was actually having."
Tam upped his activity levels by forcing himself to walk, while wife Nancy, 64, encouraged him with homecooking.
Eventually he became half the man he once was - losing more than 11 stones and seeing his waist shrink from 50ins to 32ins.
"There was just me and one another man at the class but I didn't bother about that - I had made up my mind I wasn't going to fail and I was doing this for me.
"Best of all is that I can now get back on my bike - life is great."
For more information on Scottish Slimmers classes call FREE on 0800 36 26 36 or log on to www.scottishslimmers.com