Famous for his outspoken views on politics and business – and his flamboyant jackets – the founder of former mobile phone company Phones4U is just as opinionated on health and wellness.

“Carbohydrates cause disaster,” he says, basing this view on the glycemic index (GI) scale which measures the rate at which a food makes your blood sugar rise.

Eating high-GI foods – such as white bread, white rice, breakfast cereals, cakes, cookies, carrots, potatoes, fruit such as watermelon and pineapple, sweetened dairy products such as fruit yogurts – leads to a rapid increase in blood glucose and insulin. Research suggests many diseases, such as cancer, heart failure, strokes and dementia, are caused by a combination of high blood sugar and high insulin.

Eliminating all carbs is a bit extreme, he agrees. That is why he recommends removing the “low-hanging fruit” first, and working your way down the list from bad to less bad, as he describes it.

Next on his hit list is rice – Caudwell points out that much of the world’s rice contains arsenic. Science backs that up, although arsenic levels vary depending on rice type, where it is grown, how it is processed and whether it is well rinsed before cooking.

Potatoes fall near the bottom of his list. He says they are “the least offensive, but still with a quite high GI”.

He limits himself to one or two portions of fruit a day.

“Take watermelon – it has a GI of around 72; table sugar has a GI of 63. So watermelon, if you have enough, is doing great damage to cause your glucose to spike.”

“That’s all packed full of nutrition and has very little sugar. The nearer you can get to a healthy diet, the better your chance of living longer and at high quality.”

We are here to see his new properties for sale in France on Cap d’Antibes, one of the most exclusive enclaves in the world, according to real estate agency Savills.

“It’s a must-have for me, and I find health and well-being is increasingly important to homeowners.”

He is training for a bike race traversing the breadth of Italy called Chase the Sun, on June 22, covering more than 280km (174 miles) with 3,300 metres in elevation. The goal is to get it done in a day.

Before our meeting, he had just had a three-hour sports massage, which he described as “agony, but good agony”. Regular massages help him relax.

“People don’t recognise me that way, or perhaps they do, but don’t believe it could be me,” he laughs.

Caudwell eschews having a dedicated nutritionist or personal trainer, and instead follows doctors’ and fitness specialists’ advice on their YouTube channels.

When he finds that many noted doctors are giving the same health advice, he tests their advice on himself, and if it works well, it becomes part of his regime, he says.

During his time growing Phones4U, in the mid 1990s he imported various goods from China and was often in Beijing and Shanghai.

“I desperately want to see my children grow up and I work like mad to make sure I can do the best I can. I do everything in my power to get an extra 10 or 20 years, even though I am pragmatic about it.”

“I’ve had a massive life, though, and I’m not greedy. None of us are entitled to anything.”