A SELF-CONFESSED former couch-potato transformed himself into a fitness-conscious marathon runner after a crash course in dieting saw him lose 7st 5lbs in just five months.

Jim Conway, 48, of Thriftsmead, Theydon Bois, had been overweight since 1990 with a life revolving around his sedantry office job and endless takeaways.

At his peak he weighed 21 stone, but an embarrassing encounter on a plane trip abroad saw Jim make the decision to change his life for good.

“I was flying to Morocco with some friends and I couldn’t get the seat belt on,” he said. “One of my friends came on board and shouted ‘He can’t get in, he’s too fat’. I’m used to him saying it but I could see it in the eyes of the stewardess that there was a problem and it hit me.”

After joining the LighterLife program of dieting, Jim changed his unhealthy old life for a new fitness regime with the effects proving particularly dramatic “I’m quite an impatient person, and I thought if I lose a pound a week I could still be dieting in a year’s time, but the weight just came off,” he said. “Everyone at work has noticed and I’ve had people not recognise me.”

Jim’s proudest moment came this year when he successfully completed the London Marathon raising £5,000 for charity- a far-cry from his previous life of inactivity.

He said: “It was a huge achievement. I’m doing the Dublin marathon in October and the London marathon again next year so I’ve got the fever now.”

Jim’s typical menus before and after the diet

BEFORE

Breakfast: a Full English fry-up

Biscuits and chocolate for snacks

Lunch: A couple of rounds of sandwiches and cake

More snacks

Dinner: A Chinese or Indian takeaway

AFTER

Breakfast: Bowl of cereal

Lunch: One round of sandwiches

Dinner: Grilled chicken, roast vegetables and mashed potato