It has been said that, under the old regime, Russians lived to eat, while under the current one they eat to live. But whatever the case they, like their overweight American counterparts, seem to be eating the wrong stuff. The result: Heart disease, the Number 1 killer in the United States, accounts for the greatest number of deaths in the Soviet Union. Dr. Richard Cooper, an attending physician at Cook County Hospital in Chicago, reports in the New England Journal of Medicine that heart disease accounted for "virtually the entire increase in total death rates" from 1960 to 1977 in the Soviet Union. During the period, the death rate from cardiovascular disease rose from 36 percent annually to 41 percent, with the death rate among Soviet men as much as four times higher than women, Cooper's study said. In the United States, the death rate from heart disease is 54 percent a year, the American Heart Association said. "What's striking about the United States and Soviet Union is the very high degree of similarity -- the rate of smoking, the food eaten and the high death rate," Cooper said in a telephone interview. There has been little effort to correct the Soviet problem through public education or large-scale action such as regulating cigarettes, Cooper said. "In this country, the sale of alcohol or tobacco is done to make a lot of money and that of course limits any public health effort. In a socialist country, one assumes the profit motive is not a factor." In the United States, death rates from heart disease rose sharply in the first two decades after the war, reached a plateau in the mid-1960s and declined over the past 10 years. In the Soviet Union, the death rate from coronary heart disease has continued to rise over the last 10 years and has reached epidemic proportions.