But what's on offer - served with hunks of white baguette - isn't so appetising for vegetarians or anyone looking for the five daily portions of fruit and vegetables many nutritionists recommend for healthy living. I love the food here but it's not exactly your five-a-day, said Susie Goodall, a 28-year-old British immigration consultant enjoying a glass of red wine in one of the square's bars. If you do get vegetables in restaurants they are fried. When you order a tomato salad, you get seven tomatoes covered in oil! The Spanish government, however, says what it describes as the Mediterranean diet is so good, so healthy and historical it should be promoted throughout the world.
It is leading a bid - joined by Italy, Greece and Morocco - to persuade the U.N. education and culture body UNESCO to put the Mediterranean diet on the world heritage list. Spain took the initiative ... convinced that the characteristics of the Spanish culinary model par excellence make it clearly deserving of this UNESCO distinction, said the agricultural ministry in a statement.
If Spain gets its way, the Mediterranean diet could join the intangible cultural heritage list, alongside the Festival of the Dead in Mexico and the Royal Ballet of Cambodia. It would also provide another way of marketing, even more profitably, Spanish products such as olive oil, ham and wine.
Defining the Mediterranean diet, though, is a moveable feast. When British chef Rick Stein journeyed through a number of Mediterranean countries for a TV series on the region he sampled everything from kebabs in southeast Turkey to tagines and couscous in Morocco, and salted cod in Spain.
The Boston-based food think-tank Oldways promotes a Mediterranean diet which it says is the gold standard for eating patterns that promote life-long good health.
However, the diet it recommends is based on the dietary traditions of Crete, Greece and southern Italy circa 1960 at a time when the rates of chronic disease were among the lowest in the world, and adult life expectancy was among the highest, even though medical services were limited.
MEAT AND NO VEG
Oldways and other organisations promote the Mediterranean diet which is typically defined as one with polyunsaturated fats like olive oil rather than butter and margarine, lots of pulses, vegetables, and unrefined cereals, some fish, moderate amounts of dairy products and low amounts of meat and sugar.
In Spain, though, meat is on the table in abundance. At lunchtime, blackboards outside bars and restaurants across the country announce set menus to feed hungry workers.
Favourites are fried pork chops, beef steaks or chicken breasts, usually served with chips and a miniature salad garnish. Fish is usually fried rather than the baked dishes featured in so many Mediterranean cookbooks the world over.
Spain is also battling a growing problem of obesity. The rate of obesity in adults has doubled within the last 10 years to 14 percent, while one in three Spanish children is overweight or obese - as in Italy and Greece - the highest rate in Western Europe.
The rise is blamed on factors like overeating, more inactive lifestyles and the introduction of more pre-packaged food and sweets into children's diets.
The Spanish authorities are reacting. The government asked restaurants to sign up to a voluntary code to not advertise bumper portions which it thinks encourage overeating.
Last year, in an exceptional case in the northern region of Asturias, social services removed a 10-year-old boy weighing 100 kg from the care of his grandparents because they would not stop overfeeding him.
Spain's problem with obesity does not undermine its case to have its traditional diet internationally recognised, says Chef Ferran Adria whose restaurant El Bulli was named best in the world by Restaurant Magazine.
He said it was indisputable that Italian, Spanish, Greek and Moroccan cuisine had a common culture which is one of the best in the world. The source of obesity is upbringing. Cooking healthily is very simple ... but someone needs to explain it to you. Basque chef Juan Mari Arzak, whose restaurant in the northern Spanish region has three Michelin stars, also supports the UNESCO bid. He thinks UNESCO recognition could be used like the Designation of Origin labels - seals given in the European Union since 1992 which tell consumers products meet certain standards and come from the region they say they do. Agriculture Minister Elena Espinosa has said marketing campaigns for Mediterranean products are already being run in Spain, the EU and the rest of the world. Speaking on the phone from his kitchen as he prepared tuna marinated in olive oil, rice wine and chillies, Arzak said: If this is proved (that the Mediterranean diet deserves UNESCO recognition), it would show that the cuisine is better (than others). .