January can be a difficult month for cooks: New Year's resolutions mean that patrons feel compelled to seek out lighter, healthier options. One solution is understanding the fifth taste, umami. For years in the west we thought that there were four tastes: sweet, sour, salty and bitter. In 1908, a Japanese scientist discovered a fifth, umami, and so his nation's food developed with this knowledge. But umami wasn't explored by western cooks until about 15 years ago.The discovery has shifted the paradigm: instead of considering four tastes, a chef must now take into account five and ensure they're balanced. This equilibrium is very important as it creates harmony, specifically on the taste receptors in the mouth.Much of the food they were serving in restaurants in the 1990s wasn't sustainable because it relied on seasoning, salt and fat - fine for a treat but not something you can eat every day. But when you understand that there's a fifth taste, with its own receptors, it changes the way you season.Umami is a savouriness that feels salty at the beginning but does not have that salty ''burn" that lingers. Instead it grips the mouth with a moreish tang. It's present in foods like mushrooms, tomatoes, cheese, cured hams and oysters.Stocks and sauces made from veal bones are a major source of umami.Now, rather than craving mashed potato you can get the same cosy satisfaction from umami-flavoured foods. - © The Daily Telegraph..