So John Prescott has been a secret bulimia sufferer all along. Did I spot it? Of course not. On the election campaign trail I once dined in Prezza's company at Mr Chu's, his favourite Chinese restaurant in Hull, the one where, so he says, he could eat the whole menu.
But there were 600 other people there too (it claims to be Britain's biggest Chinese) and Tony Blair was making kind remarks, evidently sincere, about JP's admirable qualities as a plain-speaking deputy. It wasn't the occasion for medical sleuthing. And besides, the food was good.
By chance I had been dipping into David Owen's new book, In Sickness and in Power (Metheun £25) when the Sunday Times began its serialisation of Prezza's Pulling No Punches memoir. As the title suggests it's a quick canter through illnesses which have changed the course of 19th and 20th century history - or not.
Did you know that President Grover Cleveland was operated on for jaw cancer (great bits of it cut away) on a yacht in New York harbour in 1893 and that they denied newspaper claims that he had more than toothache? No, nor did I.
Or that President Paul Deschanel of France leapt off a moving train and (allegedly) greeted the British ambassador wearing only his medals after developing what was probably frontotemporal dementia? He resigned after only seven exciting months in 1920.
US president Theodore Roosevelt (1901-9) may have been bipolar, as opines our medico-politician, as may Mussolini, Chairman Mao and President Lyndon Johnson of Vietnam fame, whose family had drink and bipolar in their genes, as George W Bush has dyslexia.
Hitler was not mad, he was brilliant until 1940-41 when hubris got the better of him; nor was Stalin (just paranoid), says Owen, Labour foreign secretary (1977-79) and co-founder, solo-splitter of the breakaway SDP.
FDR was frail but mentally fit to negotiate with Stalin at Yalta as Woodrow Wilson was not at Versailles in 1918.
Churchill overcame all obstacles, including depression and his own Prescottian appetite for food and drink (no puking either), between 1940-45. But was a bit of a shambles after 1951.
We know a lot of this, or rather we came to know it after the event because doctors wrote books - the Churchill family was furious with Lord Moran for breaking confidences - and the media is less compliant in helping cover things up.
In Prezza's case he has a memoir to sell and needs a few new "killer facts" to shift some copies. Tracy Temple would have been one, but the tabloids beat him to it.
What is striking about Owen's book - which devotes a LOT of attention to character defects of George W Bush and Tony Blair that led them into Iraq - is the wisdom of being candid with the public whenever possible.
Thus President Dwight Eisenhower suffered a serious heart attack while playing golf in 1955 and was incapacitated for months.
Ike's friend and doctor, who was with him at the time, did not panic, and quietly had him admitted to hospital (a similar thing happened to Churchill after his heart attack at the White House just after Pearl Harbor in 1941).
Ike insisted that voters knew what was going on. Next year they re-elected him.
Yet JFK, LBJ and Nixon did not follow Ike's example, though Ronald Reagan - a man of sunny disposition - did with his colon cancer (we got diagrams on TV) and later Alzheimer's.
They covered up the seriousness of his assassination wound in 1981 (four pints of blood lost), but Reagan was in no position to stop them.
How well do the Brits pass the candour test? Certainly better than the French. Major illnesses involving presidents Pompidou (cancer), Mitterrand (cancer) and Chirac (stroke) were covered up in recent memory.
But so was Churchill's stroke in 1953. Anthony Eden's health was appalling in office. Did Ted Heath have an under-active thyroid in his final year, 1973-74? Harold Wilson was wise enough to spot emerging senility, as others were not. He got out in time.
And Tony Blair's heart trouble, the circumstantial evidence is that he had problems for years before the voters knew. Did it affect his performance? Owen thinks not.
He blames Blair's self-belief, his actor's vanity, his religious fervour - right versus wrong - for what went wrong - in cahoots with the narcissistic and immature Bush.
Owen has invented a name for it, "hubris syndrome" which he argues affects some leaders - Lloyd George, Chamberlain, Hitler, Thatcher, Blair - but not others - Churchill, Stalin, FDR. It needs powerful controls by self, by cabinet colleagues or the voters to keep such tendencies in check.
I remember Owen in his 30s, a man who might well have headed that way, if the electorate had not decided otherwise. These days he's much the better for the chastening he received.
My impression is that John Prescott was never driven by an excessive self-belief - quite the reverse, by self-doubt; that his bulimia was private grief of a workaholic with too much on his plate - always trying to prove himself - but that his decisions were generally not the life-and-death variety which presidents and prime ministers undertake.
