Ian Marber, a nutritionist who operates under the pseudonym of the Food Doctor, says many people in the investment banking industry have an inferior diet. He provides advice on staff nutrition to financial services firms, including some of the larger US and German banks.
Marber says that the dietary failings of many bank employees are rooted in cultural factors. Popping out for a cigarette or to a café is, for example, acceptable in a way that popping out for a quick stroll is not. Drinking coffee is tacitly sanctioned by managers, while pounding the pavement is not.
Drink coffee too frequently, however, and while you may not be pounding the pavements, you will be on a rollercoaster ride between energy and lethargy. Marber tells employees that the caffeine in tea and coffee leads the body to produce extra adrenaline. This raises blood sugar levels, which prompts production of insulin, which then sends blood sugar lower.
Caffeine consumption, therefore, leads to a cycle of 'highs' and 'lows'. A more measured approach is preferable.
Snacks should include complex carbohydrates such as oats, as well as raw carrots, which provide a slow release of sugar over time.
Alcohol, nicotine and curry powder increase stress. Equally, and importantly during times of pressure, some foods have a calming effect, including leafy green vegetables, nuts, soya beans, lentils, liver and brown rice. This is because they contain magnesium, vitamin C and vitamin B5, which reduce the production of adrenaline. Without them, says Marber, the adrenal gland can get stuck on overdrive.
But unhealthy banking lifestyles have deeper roots than poor diet and coffee bars. One banking heavyweight complains: 'It's not only the fact that one starts with a breakfast meeting, which is followed by a lunch meeting, and sometimes a dinner meeting, it's also the fact that there is no time to exercise in between.'
It need not be so. Robert Paterson, a former banker, has devised a weight management course called Warriors, which is aimed specifically at businessmen with weight problems. In 1998, Paterson weighed more than 22 stone (142kg). Today, in true weight loss tradition, he is a triathlete and a shadow of his former self.
Paterson's transformation is based on time management. He says: 'The classic justification for being overweight is that there is not enough time to exercise. Weight is put on slowly over a seven- to 10-year period which often begins when men are in their 30s, have a family to support, and are focused on their careers.
'Every time you buy a new suit it gets a few inches bigger, and you reconcile yourself to that as a fact of life. It is not.'
Paterson's Warriors, who include several financiers, are encouraged to put aside time for physical activity, and to see their body as a holding company. Its efficient functioning is important to the success of its subsidiaries, namely career prospects, promotion and family life. Paterson says: 'People get so wrapped up in their careers that they lose sight of the fundamentals. When you lose your health you lose everything else.'
Paul Thompson, a managing director in Merrill Lynch's investment banking group, exercises every day, either at a gym at Barbican in the City of London, or by going for a run. He believes that exercise is good for stress control. 'People in the City of London fall into two categories - those who are pretty fit and exercise regularly, and those who hardly do anything,' he says.
Physical debilitation is bad enough, but prejudice might also affect career prospects. The New York Times reported a few years ago that only 9% of top male executives were fat, compared to some 40% of men in lower level executive positions. Fat men, the paper said, forfeited $1,000 per year, per pound of excess weight.
Mary Spillane, an image consultant, says that similar forces are at work in the City of London today. 'It is no longer OK to be a fat cat,' she says. Being fat is all the more unacceptable because for every 10 pounds of excess weight, individuals look five years older, she believes.
'When it comes to being overweight, banking is the least forgiving sector. Law is not far behind,' she says.
Spillane, too, advises her clients to exercise. But not any old exercise will do: 'You do not want to be seen as a gym drone. It is good to show that you are active and lead an exciting private life,' she says.
Mountain-climbing, cycling, possibly even swimming, hold greater kudos than the step machine, she says.
But it is to the step machine that many bankers go. Louise Thompson of the Broadgate Club, which runs gyms in the City of London and in Kensington, says that clients in the Square Mile spend half as much time in the gym as clients elsewhere. Most of it is spent on cardiovascular machines.
While huffing over imaginary hills and jogging in the direction of MTV may provide exercise, it will not necessarily alleviate stress. Gill Macleod, a consultant at the Rood Lane Medical practice, which numbers investment banks among its clients, recommends a different approach: 'Purposeful activity', such as gardening or walking, is preferable to the gym, says Macleod. She herself has taken up digging as a route to well-being.