The fitness guru Ulrich Strunz claims to have "Germany's most beautiful backside" and fingernails so hard that he can use them instead of a screwdriver. His books on jogging have sold more than 3 million copies and he charges the equivalent of £8,000 each time he appears in public to spread his message.
Known as the Doc in Teutonic health circles, Dr Strunz, aged 59, is the country's wealthiest and best-known fitness adviser.
Hundreds of burnt-out businessmen and women attend seminars run by the lithe and permanently suntanned Doc on the holiday island of Majorca each year. He is usually accompanied by his 35-year-old wife, whom he refers to as "fighting deer" because of her equally trim, doe-like appearance.
Dr Strunz's prescription for health and longevity is running and a rich-protein diet. "Movement is life. Victor mentality is eatable. Man can achieve everything through mental techniques and optimal metabolism," he claims in his publicity.
Yet more than a decade after winning the Hawaiian "Ultraman" fitness contest, which launched him on his successful career in Germany, Dr Strunz has suddenly fallen foul of the medical profession. It has denounced his methods as being little short of profit-driven quackery.
Walter Ecker, a nutritionist, described Dr Strunz's health and fitness programme by saying: "This cocksure guru, who sells himself as a sort of Pope of nutrition, knows less about his subject than the head of the Catholic Church knows about practical sex."
At issue is Dr Strunz's dietary prescription, which involves a massive intake of protein contained in the Doc's own-brand milkshakes - priced at €55 (£40) a tin - which seminar participants are encouraged to imbibe every four hours during fitness training.
Peter Steul, of the German Society for Internal Medicine, said: "We cannot exclude the possibility that this increases the risk of bowel cancer. It could also damage the kidneys." Like others, he maintains that an ordinary varied diet easily ensures the required protein levels.
Other doctors have attacked Dr Strunz's recommended "Ultralight" jogging technique, which involves running on tiptoe and landing on the ball of the foot. "Anyone who runs for several kilometres a day using only the ball of the foot is destined to suffer painful Achilles tendons - runners should always use the whole foot," said Peter Benckendorff, a renowned orthopaedic surgeon in Hamburg.
But the frequent public attacks appear only to have reinforced Dr Strunz's convictions. "If the blind had doubted Jesus Christ the way you are doubting me, they would have remained blind," he told his critics last week.
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