Festive season adds up to five kilos to the average waistline, say experts

They have warned people to stay clear of cheap produce – despite the recession – since these are poorer in nutrients and higher in saturated fats and refined carbohydrates.

Using as an example the typically-Spanish Christmas biscuits, known as polvorones, dieticians say manufacturers will increase the quantity of palm oil and lard and reduce that of almonds in order to keep the price down.

According to Dr Miguel Ángel Escartí, a specialist in treating obesity based at the IntraObes clinic in Valencia, it is possible to avoid weight gain over the festive season without having to go without or skimp on the traditional Christmas dinner.

On normal, non-festive days between Christmas Eve and the Three Kings on January 6, Dr Escartí advises to stick to the usual diet followed the rest of the year, although slightly leaner, and keep reasonably active – walking for a few minutes a day.

Frying in only a small amount of olive oil, eating plenty of fruit and vegetables and drinking at least two litres of non-carbonated water between meals, sticking to skimmed milk dairy produce and lean cuts of meat, sugar-free soft drinks, tea and infusions, grease-free clear soup, cutting out cheese, heavy sauces and nuts from salads, and keeping carbohydrates such as bread and cereals for breakfast – keeping where possible to the wholegrain, low-sugar variety, are some of the pieces of advice Dr Escartí gives for limiting the damage caused to the waistline by Christmas.

Fresh seafood and fish such as anchovies and tuna are recommended, and drinking wine, cava and cider is preferable to spirits or mixed drinks with whisky, brandy, gin, vodka or rum, since these contain a high number of calories.