Earlier in the week, in announcing her retirement from elite sport at the age of 39, the second fastest British female marathon runner behind world record holder Paula Radcliffe paid a passing tribute to the benefits of the oily fish, shellfish and seaweed which formed part of her diet during years spent in Japan.

Mara Yamauchi knows only too well the validity of Roux's jolly dictum: "Never run on an empty tum." But of course, that doesn't mean you should fill your tum with just anything.

Among those present at the lunch was the man who has shaped London into an annual powerhouse of marathon running, former world 10,000 metres record holder Dave Bedford, now the former race director after sharing that duty over the last couple of years with the new man in charge, Hugh Brasher.

Dave Bedford, former London Marathon race director, demonstrated what not to eat and drink before a marathon in 1981

Bedford famously produced evidence of his marathon fuelling - mostly liquid, it has to be said - as the BBC cameras found him on the course during the first London Marathon of 1981, a challenge he had rashly taken on for a bet during the previous night's carousing at the night club he then owned in Luton.

So let's get a relative measure on this as we learn the first truth of marathon fuelling from Dave - don't fill yourself with alcohol and curry less than 12 hours before deciding to run 26 miles and 385 yards.

But there was more measured advice to be had from amid the throng of marathon folk who had gathered in Mayfair.

Guest of honour on the day was David Weir, whose London Paralympic marathon victory in The Mall brought to a glorious conclusion a Games which had already seen him win three track golds in the cacophonous cauldron of Stratford's Olympic Stadium.

David Weir in the marathon at London 2012 on his way to his fourth Paralympic gold medal 

In the aftermath of his marathon, an exhausted Weir had leant over his bike and confided that he was already looking forward to a long-promised getaway with the lads in Ibiza, where, he maintained, drink would be taken.

Weir got his break, at the insistence of his partner  Emily, but it was far from a relaxing time as he was concerned about complications in her pregnancy which, happy to relate, turned out fine as she later delivered a happy and healthy daughter – Tillia Grace London Weir. "I did drink a lot, but I wasn't able to relax much," recalled Weir, whose presence was later marked by the presentation of a hand-painted racing helmet emblazoned with the face of a snarling wolf – in tribute to the alter ego of the Weir-wolf which the media and public appended to him during the 2012 Games.

While wolves like the odd bit of raw meat, the closest this Weir-wolf gets to it – but only during his down-time - is a burger.  "I did like a McDonald's after the Games, I did like a curry and stuff," he said. "But once you are back in that training mode it all goes.

As you might expect, Weir – who has been braving the sub-zero temperatures as he trains for what he hopes will be a record seventh London title, bettering the total he currently shares with Dame Tanni Grey-Thompson - fuels for performance in a big way.

"High carbs," he said. "Very high carbs. Lot of pastas. Maybe between two and four massive pasta dishes, because I find that pasta is the one which gives me most of my energy, more than potatoes and rice, even though I eat them too.

"Because I will be training in the mornings it will be in the afternoon and the evening before.  I don't have the bowls one after the other – I space them out, have them with chicken or sausage meat."

Asked whether he needs to alter his diet according to whether he is competing on the track or the road, Weir responded: "Not really no, because when you think of the mileage we do on the track anyway it doesn't make much difference. You stock up as much as you can. But you have other things to do to get the power out as well, you use things like protein shakes."

David Weir celebrates winning the 2012 London Marathon, the sixth time he had triumphed in the event

Pasta rules the Weir diet – but not exclusively. "'I'll have beans on toast for lunch, or sometimes have a really good salad where I have mackerel and tuna with it," he said. "And some beans on the side so you've got some sort of carbs in it as well, and new potatoes maybe. I do some of it, but my partner cooks quite a bit for me too. Sometimes the food is waiting for you when you get back, which is pretty nice."

Asked which meal, given an absolutely free choice, he would most like to tuck into, Weir responded, with just a trace of wistfulness: "I like roast dinners. So that would probably be the one."

As Weir fantasised about beef, Yorkshire pud and all the trimmings, Roux was preparing to oversee the delivery of a lunch which, as he was frankly to advise all present, was far from an ideal preparation for an afternoon training run.

His own running has been hindered in the last three or four years by a persistent calf injury, but he now has a routine involving less running, rowing in the gym, swimming, massage and rest which allows him to keep up his stamina and fitness levels. "It will never fully compensate, but it gets me through races," he said.

Michel Roux is a regular participant in the London Marathon

Roux is similarly convinced of the benefits of routine when it comes to fuelling for performance.

"The day before a race or a long training run I always say you should eat what you normally eat, don't go silly and eat something you have never had before," he said. "Don't risk anything like that, spicy food or whatever, it does tend to linger in your tummy and it's not particularly nice. You stick to your routines. Don't change your routines. That's the most important tip I think.

"The night before a run I tend to eat something like grilled fish and boiled potatoes for dinner. I do have a glass of wine. But just a glass. I find it helps me relax and I can go to bed as peacefully as I can after a reasonably light dinner.

"I tend to start running in mid-morning. I like a breakfast beforehand. I normally say you should not run on a completely empty stomach. So I will have black coffee –expresso - toast – made from home-made bread - and home-made jam or marmalade. Some Brittany butter as well.  It works for me but it may not work for someone else. You have to find out for yourself. Don't change."

Roux admitted that if he went out for a run without having had some proper food, he felt a bit vulnerable.


Michel Roux, owner of Le Gavroche, does not believe you should run on an empty stomach - although this is probably not what he had in mind

"Yes I do, most definitely," he said. "So what I will do sometimes is I will have a breakfast and just before I am rushing out of the house I'll have a slice of fruitcake or a handful of dried raisins. I'm not keen on these ultra-sweet gels, which I have trouble digesting. I don't mind the drinks, although I'll water them down because I still find them hugely sweet. But I won't take any food with me for a race. Nothing. On a training run I'll take a bottle of watered-down drink and that's it.

"There was a London about four or five years ago when it was incredibly hot, and I was guilty of the cardinal sin of drinking too much water. I felt very sick and giddy afterwards and got my wife quite worried.

"I think that's more dangerous than not drinking enough and I think not enough is said about that. You've got to be careful and not just gulp down water for the sake of it, thinking that you need. You don't need to take liquids on board at every single station."

There was also once a big misjudgement on the food front by Roux, as he admitted.

"A few years ago I ran the Tromso Midnight Sun marathon in the Arctic Circle," he said with a faint grin. "Because you start running at 10 o'clock at night it puts a spanner in the works.I wasn't sure what to do in the day before, but then I thought, 'when in Rome...'. So my wife and I found a restaurant which, although it was not in the guide book, was very full. And it had a very strong, lingering smell about it.

"When I asked the Maitre D' what was Special, what he did best, he offered me either prawns or grilled whale steak. And I thought 'why not have the whale steak? You might as well try it while you are here.'

"When they served it to me it was on a T-bone, a massive piece of meat with lots of fat attached to it.  I ate a big part of it. I knew then what the lingering smell was – whale meat. And it wasn't very nice!

"I regretted that meal until I reached mile 24 – it was very, very heavy, and I kept on burping it up all through the race. I finally digested it after about eight hours. It was not good."

Needless to say, whale meat was not, and never will be, on the menu at Le Gavroche.

Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five summer Games, and four winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, the Sunday Correspondent and The Guardian.