Maybe it's the onset of summer and the thought of cramming bodies into too-tight swimming costumes, but there is a sudden mood of restraint in my office.
There is only one man still consuming colossal quantities of pizza and Kentucky Fried Chicken at regular intervals throughout the day, but everybody else is counting the calories and coming out with different means and methods of reducing the waistline.
Those of us who have lived in France will know it's a myth that Frenchwomen don't get fat. I have friends in Paris who swear there is a van that goes round in the early mornings and rounds up anybody at all rotund and takes them away for the day, only releasing them after dark.
Dieting the French way remains a growth industry. First there was a Frenchman whose name I have forgotten, followed by the Frenchwomen Don't Get Fat by Mireille Guiliano, who also wrote a cookbook telling you how to cook things that won't make you fat, to chew slowly and drink a glass of water.
But the real winner is Dr Pierre Dukan, with The Dukan Diet, The Dukan Diet Recipe Book and The Dukan Diet Life Plan. He has sold about half a million of each book in France alone this year. It seems once upon a time the French taught the world how to eat; now they are teaching us how to stop.
And you can see why Dr Pierre is so popular. His diet is full of food, especially "Protein Thursday", and you have to drink gallons of water every day and exercise, but you must lay off the carbohydrates and especially potatoes.
"The idea of Protein Thursday has taken off in France to such an extent that if I find myself in a restaurant with my family on a Thursday, I very often hear other customers around me asking for their fish or meat to be served straight, without vegetables or salad," the Doc told a British newspaper.
But the slim doctor is rather angry. A rival nutritionist in France has accused him of being a quack. When asked who benefited from the Dukan diet, Jean-Michel Cohen replied: "The slimming industry, doctors, pill salesmen, publishers, newspapers … Everyone who has climbed on to the bandwagon of this fantasy."
A court in Paris is now deciding which of the two is right. The business desk may be a bit slow on to this bandwagon. One of our colleagues has just celebrated her first anniversary of following The Dukan Diet, and now she is a slip of a thing, a shadow of her former self. In fact, she has lost so much weight she is being allowed back into France.
I don't hold with diets - the very word makes me want to go and consume a few rounds of hot buttered toast - but I did meet a banker the other day raving about a diet he was following called The 4-Hour Body. It is written by Timothy Ferriss, a rather eccentric young American whose previous book, The 4-Hour Workweek, was a best-seller everywhere but France, where they thought it sounded a hideous amount of time to spend in the workplace.
Mr Ferriss is a tango dancer who holds the world record for "spinning", whatever that is, outsources the reading of his e-mails to somebody else, does Chinese kick-boxing and is a relentless self-publicist. But he has cobbled together an impressive sounding number of tenets to live by, including Pareto's Law, which suggests about 80 per cent of the results of any endeavour come from just 20 per cent of the effort and time put in. Why put in more than 20 per cent effort? he asks, and he has a point.
The New York Times said his book reads as if "The New England Journal of Medicine had been hijacked by the editors of the SkyMall catalog". I don't know what the SkyMall catalog is, or even if that is the right way to spell it, but the book certainly sounds mad.
"Overfat? Try timed protein and pre-meal lemon juice. Undermuscled? Try ginger and sauerkraut. Can't sleep? Try upping your saturated fat or using cold exposure," Mr Ferriss writes in an extract.
I don't understand a word of this. The answer is to avoid French dieticians, mad American self-publicists and beaches, and if you must go swimming, wear a burkini.
Far better to head straight to Beaujolais Restaurant on Hamdan Street, which feels like France in the 1950s, where it is still acceptable to eat a proper lunch, even if it ends at cocktail hour.