BUCHAREST -- Severe shortages of such basics as produce, meat and energy have turned shoppers into scavengers and have left many residents of this Romanian capital preoccupied with making ends meet.

Six years ago, the regime of Romanian communist leader Nicolae Ceausescu launched an economic austerity program. The results -- meager food and energy rations, Europe's longest work week and a reduced choice of entertainment -- have driven Romanians to spending more and more of their day gathering food and finding ways to keep warm.

"Not so long ago, Romanians used to be among the most thriving people in this part of Europe," one Bucharest-based western diplomat said in an interview. "Now when I look at what's in the stores and I read the restrictive laws, I wonder how they survive. On paper, they should not be able to survive."

Finding food has become a national obsession. Recently, a Romanian student interrupted a casual conversation about literature with an American visitor and turned abruptly to the subject of food. "You probably don't even think about it," he said, describing another day without meat, "but we think about it all the time."

On a main street corner the same evening, a young professional, well-off by local standards, collected change from passers-by. "My wife can't find a job and we have a daughter," he explained. "I have to feed them somehow."

Two weeks ago, a rumor spread that cheese might be sold on a busy street corner. This drew a crowd, jeers and hours of anxious waiting -- but the cheese never materialized.

The whole country seems to be fighting a losing battle with food shortages. In Brasov, 100 miles north of here, city council vice president Maria Cebuc told of a practice of calling all local factory workers, office employes and students out to the fields to harvest potatoes and sugar beets every fall. In the winter, exhaust steam from factories is pumped into greenhouses to help grow vegetables, she said.

Once the harvest is in, however, so much of it is exported to Western Europe and the Soviet Union in exchange for oil or other basics that little is left for public sale here.

During the summer, scattered supplies of eggplant, peppers and tomatoes provide some relief from the basic Romanian diet of bread and grain -- much of it cornmeal ground into a mush called mamaliga. But in winter, fresh vegetables are nowhere to be found, and, lacking meat, shoppers clamor for supplies of bones.

While housewives in neighboring Hungary and in Austria store summer vegetables for winter, tough laws deter Romanians from stockpiling food. Those found hoarding more than a month's supply at home face stiff prison terms. In 1983, five Romanians were given death sentences for stealing meat, according to an Amnesty International report on Romania released this summer.

Some Romanians resort to an active black market trade in food, particularly meat. With strict fines against possession of hard currencies, the under-the-counter trade is usually conducted with American cigarettes. Since cigarettes are neither produced nor sold on the open market, offers of brands such as Kent or Marlboro often lead to supplies of otherwise invisible meat.

But black market rates can be steep. For two pounds of beef, for example, Romanians may have to give restaurateurs up to four packs of Kents -- worth the equivalent of $40 at the official exchange rate.

Often shoppers leaving a food store will go to the end of the long line outside and sell part of their purchase for double what they paid, a western diplomat said.

Coping with closely rationed energy supplies poses even bigger problems, particularly in winter. Under restrictions imposed last winter, each household is allowed to use one 40-watt light bulb in the evening for heat and light. Since violators risk having their electricity cut off, Romanians have little recourse but to wear heavy overcoats, blankets and quilts indoors.

Last February, the restrictions led to such severe conditions at a university in Iasi, a city on the Soviet border, that 700 students revolted, according to diplomatic sources here. In an angry demonstration, they complained that without lights or heat they could not study.

In a rare conciliatory move, the local party in Iasi agreed to increase energy supplies, the diplomats said.

With a 46-hour work week, Romanians look to entertainment to alleviate the tensions of the daily grind -- but few entertainment options are available.

Dining out is usually unaffordable, and in any case not much fun, given the chronic shortages of food in restaurants. Gasoline is rationed outside Bucharest, and pleasure driving is allowed only on Sundays. Because little money is available to make movies or import them, the state-controlled movie theaters show mainly films of the 1940s and 1950s. Television features only two hours of programming a day.

One form of entertainment that has become popular here is television broadcast by neighboring Bulgaria. It is considered dull by western standards, but here crowds gather at the window of Bulgarian Airlines' offices to copy down the times of TV shows posted there.

When soccer games and other popular shows are broadcast from across the border, Romanians can be seen with their television sets attached to cars parked on hilltops facing Bulgaria.

For the average worker here, pay is scant, averaging 2,500 to 3,000 lei (about $250 to $300 at the official exchange rate) a month. But even for those with bigger salaries, the outlets for spending are narrow.

"With food falling into deeper shortages every year," one western diplomat said, "every year we think the whole thing is going to collapse. And then, somehow, the Romanians seem to adjust. I don't know how. Nobody knows."