The country is one of the world’s food hot spots. Miraflores, the area of Lima where the Scottish team is based, is viewed as South America’s foodie capital. Still, it’s not common to be talking to a Scottish footballer about turning vegan, which, to all intents, is what Mulgrew has done after noting health scares in his family history.

The younger members of the Scotland squad have not quite bought into it. “They’re boaking when my lunch comes out,” says Mulgrew.

But it’s an important issue which Mulgrew is right to take seriously. His father has had a heart attack and his father’s parents both had heart attacks in their early 70s brought on by high cholesterol levels. So what Mulgrew did not need in his Celtic days was a dietitian recruited by Ronnie Deila telling him to eat more meat.

“That was the complete opposite (of what I’m doing now). It was the caveman diet: high fat, just meat,” he recalls.

“My body fat was low, I was ripped. I was injured at the time so it was easy for me to do. But when I went back training I had a lack of energy and my cholesterol was through the roof. And I have a history of heart attacks in my family.”

His protests were met with advice to increase his meat consumption. “The dietitian who came in was brainwashed to think this was the way to do it,” he says. “To be fair, it stripped everybody’s fat, everybody’s body fat was down. But that doesn’t necessarily mean you are fit enough. It is hard when someone is brainwashed to then say ‘that isn’t working for me’ because they say ‘you need to do it more’.”

When he eventually had his cholesterol checked by the club doctor, it had doubled, hence his new outlook now. Not that he has been guided down this road by a professional dietitian. Rather, he was influenced by documentaries on Netflix.

“I’m easily led,” he smiles. “That’s basically it. I have just tried to educate myself on eating and that sort of stuff. I’ve felt brilliant on it. When you’re young you eat a kebab at three in the morning and then you train okay and you think ‘I might just keep that going’. But you realise as you get older the wee margins make  a difference.”

Mulgrew believes he is  fitter now than when he was 19 years old and in his first spell with Celtic.

“It is hard,” he adds. “I don’t tag myself as vegan because I might go up there (to the hotel restaurant) and have a scoop of ice cream after my lunch! But it’s hard, because you need to work out how to cook. We’re brought up thinking meat, carbs and veg is a healthy meal. But now you need to base it all on veg really. You need to swap chicken with sweet potato and that sort of stuff. It’s not easy.”

Helpfully, his wife, Alana, has been swept up in it too. “She’s the same, she’s up for all that stuff,” he reports. “To be fair I do most of the cooking now. She’s learned to cook a few things as well but both of us do it. There is still the whole chicken nuggets thing for the weans, we can’t turn them!”

Mulgrew himself would once have turned his nose up at the mere suggestion of a plant-based diet. But he realises that in order to prevail at a high level you must consider treating your body with more care. Other high-performing sports people such as F1 Lewis Hamilton and tennis sisters Serena and Venus Williams have recently converted to a vegan diet in a bid to remain at the top for longer.

Mulgrew, recently installed as captain under new Scotland manager Alex McLeish, has every reason to want to prolong his career. As he says himself, you’re a long time retired. It is heartening to hear there was never any question of him trying to avoid coming on tour to Peru and Mexico with  Scotland.

Now 32, he has just been promoted back to the Championship with Blackburn Rovers, the club he joined from Celtic two years ago. The aim is to get back to the English Premier League, where former Scotland manager Gordon Strachan, one of his mentors, was still playing at age of 40. He was famously aided by a diet consisting largely of bananas and seaweed.

“He’s an influence on me,” says Mulgrew. “I had good chats with him. He has good views on keeping fit and stepping up your training rather than bringing it down as you get older, and training how you play and that sort of stuff. I’ve become a big believer  in that.”

Charlie Mulgrew rejects '˜caveman' diet as he becomes a vegan