With an alcoholic dad, a struggling mum and little to no food on the table, young Barry Gunn would count the days to the weekend and his granny’s kitchen.

There he would watch her transform minuscule cuts of meat into hearty meals. A few vegetables would emerge from the pot as thick, warming soups that coated his tiny ribs, and the aroma from baking scones, cakes and biscuits made his hungry tummy rumble.

His wee Glasgow granny Lizzie McNab, with her bushy white hair and adoring smile, put well-loved family recipes into his belly which, until then, could easily have gone days without a proper meal.

Inspired by her humble skills, Gunn would go on to leave school at 15 to become a chef. He cooked for royals, A-list celebrities and in some of Glasgow’s best-known restaurants, but his nana McNab’s dinners were, he recalls, the best he’s ever had.

“My mum did her best,” he recalls. “Dad was an alcoholic, and we were poor. We didn’t have a great understanding of good-quality food.

“My nana was the best cook on the planet. She was a magician. She could turn a pound of mince into a pot that could feed 15 people.”

As well as nourishing her ravenous young grandson, nana McNab laid down a lifelong appreciation for the power of food: the way it tasted, the smell, the excitement of discovering a new ingredient and the deep satisfaction of sharing it with others.

Now, years later, those valuable lessons learned in her Garthamlock kitchen are being passed to a new generation of vulnerable young people, some of whom – like him – know the misery of going hungry and who have rarely eaten a fresh vegetable or piece of fruit in their lives.

Now a chef lecturer at Glasgow Clyde College, Gunn is tasked with nurturing students who on paper may have poor prospects. Few who join his Clyde Kitchen course have any qualifications, some lost interest in school years ago, many come from deeply troubled backgrounds, and most arrive without the benefit of having learned even basic kitchen skills from parents or family.

However, the combination of Gunn’s passion for cooking combined with his own deep understanding of the challenges they face has led to remarkable results.

On the college’s eighth floor, Clyde Kitchen students who seemed doomed to drift through unemployment serve healthy salads and dishes from around the world at Eat On 8, a not-for-profit, Fairtrade cafe where they make and serve global cuisine to students and lecturers, taking charge of everything from meal planning to pricing and stocktaking.

In some cases, he’s seen students arrive having rarely seen or eaten fresh fruit and vegetables, so wary of some international dishes that they initially refuse to believe they will one day eat, never mind cook, them.

“On week one, they’re saying to me ‘I’m not eating that’. By week four they’re cooking and eating vegetarian meals and dishes they’ve never heard of, and loving it,” says Gunn. “It opens their knowledge and their palate.

“A lot of them are very vulnerable, from broken homes, foster care. Some are from families that have alcohol or drug issues and were not given proper opportunities in life.

“They have missed school and had little education or desire to be educated. They’ve maybe been in a bit of trouble with the police or maybe someone doesn’t want to give them a chance.

“I appreciate some of the difficulties that they face.”

Every student who completes the 16-week course receives pass marks. From there, an estimated 95% go on to either find work or enter further training, many of them in the catering and hospitality sector. It’s likely that every one of them learned more about fruit, vegetables and nutrition during the course than in their entire lives.

Meanwhile, as well as turning around young lives, the steady flow of new students is playing a small part in helping to plug Scotland’s hospitality and catering skills gap.

Gunn, who watched his grandmother and mother struggle with no reading or writing skills, says watching the disengaged young students blossom sparks memories of his own difficult childhood.

“I grew up in the east end, and every weekend we’d stay with my gran who made sure we were well fed at least twice a day instead of it being once or not at all.

“She taught me to cook and to love food. If there was some food I wanted to try, she would scrimp and save and get it for me. It made me think about flavours.

“Growing up was tough, there was a lot of alcoholism and violence. I had a terrible attitude at school.”

He left school with little prospects at 15. However, a training job in a kitchen that paid just £33.10 a week was life-changing.

By 19, he had worked his way through Glasgow’s Spaghetti Factory in Great Western Road, O Sole Mio at the North Rotunda and L’Ariosto in Mitchell Street to become head chef at a Glasgow Slovenian restaurant, Miško.

Around that time his 21-year-old brother, David, was murdered, stabbed through the heart after a night out at the city’s Metro Club. He distracted himself from grief by working even harder.

Gunn cooked at exclusive Skibo Castle, serving breakfast to actor Jack Nicholson in the hotel kitchen to avoid the stares of other guests.

One of his proudest moments was preparing dishes for the Prince of Wales and Prince William during a visit to Glasgow’s Lighthouse in 2001. Having lavished love on the dishes, Prince Charles instead requested a plain egg sandwich.

It was while cooking for corporate events at Hampden Park a couple of years ago that Gunn realised the long hours and high demands of the kitchen were no match for family life.

He joined Glasgow Clyde College three years ago to run the Clyde Kitchen programme at the Cardonald campus. Targeted at 16 to 24-year-olds, it gives them practical experience running the Eat On 8 café, teaching organisational skills, kitchen hygiene, cookery, and core skills such as communication and numeracy.

Clyde Kitchen was so successful that a second, similar course for students who use English as a second language – including refugees and asylum seekers – was launched. It too has achieved a 100% pass rate among students, with almost all going on to find work or to further training.

The hardships they have faced has left even Barry, with his tough upbringing, humbled.

“These students are the most wonderful people, their stories are heartbreaking. They are desperate to work and give something back to the UK,” he says.

“They are so hardworking and give 100%. I feel privileged to be able to help them.”

All of his students know about his grandmother.

“I speak about my granny, I tell them how she cooked and what food meant to me. They know I came from the tougher end of life and know what they are going through.

“My grandmother died from cancer when I was 15, so she never saw me make this my career,” he adds.

“She would probably be proud that what she taught me is now making such a difference in other people’s lives.”