January 5, 1983

A former economist with the Federal Reserve Board who left to work for a brokerage firm was charged today with illegally tapping the Federal Reserve's computer to obtain secret data about the nation's money supply. Federal officials said that soon after joining E. F. Hutton as a forecaster, the economist, Theode C. Langevin was caught by tracing the phone calls he made to the computer. Officials then let him tap into a computer programmed with phony money figures so that he could be caught ''with his hands in the cookie jar,'' an official said. Money supply data, if obtained in advance of its release each Friday by the Federal Reserve, would be of tremendous value to a forecaster working in a brokerage house that trades in stocks and bonds. Interest rates and yields of Government securities and bonds often move up or down when changes in the growth rate of the money supply are reported.

Years ago, when her husband was working as a clerk on the State Court of Appeals, Matilda Cuomo used to stand outside the wrought-iron fence of the Governor's Mansion and stare. ''I was in awe,'' she recalled. ''I would stand by the fence and I'd say, 'My gosh, that's where the Governor lives.' '' Today, in her fourth day as a resident of that mansion, Matilda Cuomo retains some of that awe. Drinking coffee served from a silver tray, she looked around her at the elegant living room and said, ''I think it's something like a dream that I find myself here.''

THE 1982 food year was one of fresh fads and fervid fitness, explored cuisines - Mexican and ''gourmet'' convenience foods'' among them - and expunged demons, namely salt and caffeine. Americans continued their helium-fueled search for lightness in everything from cereals and spaghetti sauce to wine -even that insouciant big guy on the block, Coca Cola, acknowledged that it was time to go on a diet. It was a year when old infatuations faded (nouvelle cuisine conceits) and new phoenixes rose from their crumbs (new American cuisine). It was also a year that spawned everything from the fanciful (spinach bubblegum, kosher tofu) to the fatuous (Paul Newman Salad Dressing). Certainly the soaring interest in Mexican food in a recession year can be attributed, at least in part, to the fact that it is so economical. Yet despite the recession, Americans seemed more willing than ever to experiment. According to Progressive Grocer, a trade magazine that monitors food spending, Americans were expected to spend about $252 billion in groceries during 1982, an increase of about 5 percent over 1981. Taking into account the softening of inflation, that is considered not only a more than respectable growth, according to food industry analysts, but also an indication that there is room for new and exotic foods.

With the international banking system in crisis and with domestic competition intensifying, the National Westminster Bank, the world's ninth largest in terms of assets, is undergoing a changing of the guard. Since last August, the retirement of a handful of senior executives has touched off promotions and job switches that leave nine of the bank's 11 top executives in new positions. And today, in the most important change, Philip Wilkinson, a solid, silver-haired man who describes himself as ''not all that colorful,'' moved up to the post of chief executive officer. He succeeds W.J. Benson, who becomes deputy chairman in place of the retiring Alex Dibbs.

FOR those who love their food rich and calorific, January, not April, is the cruelest month. This is the month of reckoning, the time when recipes calling for heavy cream, chocolate, sugar and perhaps even Champagne, truffles and caviar, are replaced by those calling for broccoli, turnips, pinto beans and oranges. It is the month for retrenching or following new resolutions, for saying ''Enough!'' to superrich dishes. People who forsook their diets at Thanskgiving and never quite returned know that now they have to pay the piper. There is a good side of all this. Turning away from chocolate mousse cake and filet mignon to fruit salad and ground turkey is not only a boon to the waistline, it is also a boon to the budget, as well as an opportunity to save time in the kitchen.