A FEAR of missing out on his four-year-old son growing up prompted an overweight Gourock dad to lose five stones in barely three months.

Martyn Donnelly tipped the scales at 21st last September before taking drastic action to improve his health.

After years of failed attempts at dieting, the 35-year-old turned to exercise, joining Gourock Gym in September.

With the help of fitness advisers, he shed a staggering amount of weight.

Martyn, who lives in Midton and works nightshifts at Amazon in Gourock, said: "Another year and it could've been a heart attack.

"I've always been a yo-yo dieter and for years I would lose a lot of weight then put it back on.

"One day I decided to try the gym and knew I would catch the bug and I did.

"Takeaways and drink was my big problem but now if I want a Chinese meal, for example, I can still have one.

"I just watch what I eat and go to the gym.

"I feel better generally, healthier and I can run about and do stuff with my four-year-old boy."

Martyn is now down to 16st and has also dropped from a size 44 waist to a 36 and from a 5XL t-shirt to an XL, but says he still has more to do.

He said: "I'm definitely not finished, I'm not even half-way through my journey. "The more you see the results the more you want to keep going.

"It's not a fad or a quick-fix, it's a lifestyle change.

"I was apprehensive about the gym at first because there's folk at the gym who are well built but I took that important first-step of actually going and the staff make you feel comfortable and that you can achieve what you want to.

"They're so friendly and motivate you to do it."

Graeme Wallace, a fitness advisor at Gourock Gym, said: "You have to be committed and want to do it and Martyn is a great example that the gym does work.

"What he's achieved is amazing."

His colleague, Jonny Anderson, added: "He's done so well and it's brilliant to see.

"It's great to have someone like Martyn to inspire others."