When Zaheer and Saira Khan lost their seven-year-old son Sultan in 2004, they hit an all-time low.
They struggled to cope and it heavily impacted on their health, resulting in piling on the pounds.
But as they slowly regained their life, they realised they needed to change their lifestyle and sought help from personal trainer Michelle Orrell.
After two years and a combined weight loss of almost nine stone, they are both preparing to run the London Marathon.
Zaheer, 49, will be raising money for Marie Curie and Saira, 41, is hoping to boost funds for Great Ormond Street Hospital.
Zaheer, of Catforth, says: “Sultan was a normal, healthy seven-year-old boy. He felt fine and there was nothing physically wrong with him, but we noticed the colour of his eyes were slightly yellow.
“We took him to the doctor, who confirmed he had jaundice, but it was not a big deal and it could be treated.
“But after a couple of days, we got a phone call to come in to Royal Preston Hospital for more checks.
“It all escalated from there and he died 14 days later.
“He had liver problems and he had to go to the Diana, Princess of Wales Children’s Hospital, in Birmingham, as his condition was a lot worse than we thought.
“He needed a liver transplant but there was not a match at that time, but as soon as there was one they would let us know.
“At the last minute, we were told there was a donor, with a 70 per cent chance of it going well. It was a life or death situation, so we decided to go through with the procedure.
“The following morning, he started bleeding internally and he died in September 4 2004.
“We were heartbroken. He had everything to live for. He was such a beautiful, nice lad.”
Zaheer, who has five other children, had to cope with things in Birmingham alone, as his Saira was at Alder Hay, after their baby daughter was suffering heart problems.
Zaheer adds: “It was a double tragedy for us, as our daughter Miryam, was born a few months before, in May, but had developed complications with her heart. Luckily she pulled through and she is 14 now, but she still has some problems like arthritis.”
As the couple were grieving for the loss of Sultan, they turned to easy, convenient food and led an unhealthy lifestyle.
Zaheer, a refrigeration engineer, weighed 18st 7lb, whilst Saira was 11st 7lb.
But when Zaheer wanted to get fit before his 50th birthday, they sought help.
Zaheer adds: “When you have this kind of blow, it creates a big impact psychologically and physically.
“It really took its toll for 13 years.
“We would eat take away, drink fizzy pop and munch on a lot of snacks, like crisps and biscuits.
“But I wanted to get myself in order before I hit 50, so two years ago we started training with Michelle.
“We trained outdoors in the park, running and doing high intensity workouts, trying to get our weight down.
“We started eating healthier and I have even given up meat.
“We train with Michelle two or three times a week and I swim every morning before work.
“We got our lives in order, and I am now 12 stone, and Saira is nine stone.”
With their new lifestyles, they took on running challenges, and Zaheer ran the half marathon in Liverpool last year.
They are now ready for the London Marathon on April 28.
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Zaheer adds: “I never thought about the marathon while I was on this journey. We were just getting ourselves in shape but we thought we could raise money for good causes.”
To support Zaheer and Saira donate to www.justgiving.com/fundraising/zaheer-khan1969