Rhiannon Harries: 'Why is no one criticising Sir Cliff for his crazy diet?'

One meal a day, occasional fasting, no wheat, no dairy, various vitamin and mineral supplements, regular five-mile walks and work-outs in the home gym. Now, who would follow a regime like this? Jennifer Aniston in pre-Oscars mode? Trudie Styler on holiday?

If you're surprised to learn that it is in fact our erstwhile British Elvis, Cliff Richard, you shouldn't be. How else do you think he has maintained that 30-inch waist and those boyish good looks right up to his current age of 69?

If you haven't heard, Sir Cliff has a 2011 calendar out. Actually, such is his popularity he always has a calendar out (well, you know, once every 12 months) – and it consistently outsells comparative whippersnappers such as Becks poncing about in their shorts. But thanks to this one, everyone has got a little bit excited about just how good Cliff looks for someone a month short of the big three score years and 10. And, you have to say it, the man does look good. A little bit like a sandwich that's been refrigerated in Tupperware for a couple of days – slightly curling round the edges – but all right.

On one hand it seems only fair that we celebrate the fine figure of a man of advanced years. Based on the selection of poolside pap shots of other rich and famous males that we are generally treated to each summer (Simon Cowell, Philip Green et al), I'd say Cliff is alone in his continued dedication to his physique.

And what dedication. Cliff has not been shy about letting us in on his beauty secrets. He follows a diet that works out what you should eat based on your blood group, skips food altogether occasionally, and takes lecithin to prevent fat storage. He does have a glass of red a night, but the man owns a vineyard, so he could hardly say wine's bad for you. Basically, Cliff was Madonna before Madonna was Madonna.

Is it wrong that I find it satisfying to hear, for once, a man describe the joyless minutiae of dieting? In a very mean-spirited way, I'm glad that the odd male brain cell is wasted on the purported benefits of lecithin. Less pleasing is that Cliff gets away with talking about this stuff without being branded a fool.

Yes, there's the odd snigger about the eternal bachelor boy, but on the whole his ultra-clean living is considered impressive. Put the same words into the mouth of Gwyneth Paltrow, Victoria Beckham or indeed Madonna and they are vain, toxic influences. Which may be true, but I'm not sure why Cliff is exempt. He's clearly as fixated on getting into his skinny jeans as Mrs B. Perhaps it's because nobody is likely to emulate him? You never know, though: he has sold 1.5 million calendars.