The Hairy Bikers stars Dave Myers and Si King both got massive wake-up calls after Dave reached 18 stone, and Si 19.5 stone.
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In 2012, Dave was diagnosed with borderline Type 2 diabetes, while Si had particularly high blood pressure.
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A doctor and friend showed his concern at the time and said: "Look lads, you're middle aged now and morbidly obese. You need to do something about it."
Speaking out about their weight gain in 2017, Dave admitted that they both needed to take stock of their health: "If we'd continued to pile it on the way we'd been doing, we wouldn't have had a career anyway – you can't if you're dead," he said.
The turning point for Si came when he suffered a brain aneurysm in 2014.
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© Photo: Getty ImagesDave Myers and Si King in 2010
"The doctors did a lumbar puncture and found blood in my spinal fluid," he explained. "At that point they grew really worried – I had to sign a load of forms to say I understood I may make it, or I may not. It was scary for me, but I think it was even more difficult for my kids and wife Jane at my bedside."
He was rushed to hospital to have an operation to stop the blood, before he then spent four days in therapy and couldn’t do much for eight months as he was told he had lost "20 per cent of himself".
© Photo: Getty ImagesDave Myers and Si King in 2012
At this point, Si had already lost some weight and said he wouldn’t have survived if he hadn't, but he went on to regain the weight he had lost during rehab. He decided to shed the weight again as soon as he was well enough.
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"About six months ago I decided it was time to start losing weight again," he added. "In aneurysms high blood pressure is an issue so if I hadn't lost all that weight with Dave in 2012, I probably wouldn’t have survived. That is a good incentive to get healthy again." Si is father to sons Alex, James and Dylan.
Dave's diabetes diagnosis was what opened his eyes. He told the BBC: "It was a wake up call for me. I always knew I could be a bit on the greedy side; I love cooking and eating and there in front of me was the evidence which I would have been daft to ignore."
They've since lost an impressive six stone between them. So, how did Dave and Si do it?
© Photo: BBCDave and Si had to invest in new wardrobes
Dave said: "I always lose weight by cutting all the carbs out. I just calorie count and knock the booze on the head and then watch the scales to see the weight come off."
Si says that getting on the scales is what motivates him: "We get on the scales and encourage other middle-aged blokes to do the same," he explained.
To note, while cutting out carbs worked for Dave, it's by no means a fool proof route to weight loss. In fact, carbs contain key nutrients, and a deficiency could be detrimental to your health. The NHS explains: "The idea that 'carbs are bad' has left many people confused about carbohydrates and their importance for our health, including maintaining a healthy weight.
"Carbohydrates are a broad category and not all carbs are the same. It's the type, quality and quantity of carbohydrate in our diet that's important," while, "Significantly reducing carbohydrates from your diet in the long term could mean you do not get enough nutrients, potentially leading to health problems."
Davie and Si have now lost so much weight that they've even been able to stop taking medication. "I was told that I could stop taking the blood pressure medication I was on. It was a small dose but not having to take the daily tablet is great," Dave said. "Coming off medication is the best thing that has happened for both of us. There is no downside; the only thing is I am spending a fortune on clothes that before the diet I only dreamed of wearing. Some of my wardrobe monsters are making a re-appearance... wait till you see them on the telly."
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