The multiyear study, published Tuesday in the Archives of Internal Medicine, also found that less than 10 percent of the more than 23,000 people in the study actually lived their lives this way. 'The study has such a simple straightforward focus on making the point that prevention works in preventing serious disease,' said Dr. J. Leonard Lichtenfeld, deputy chief medical officer for the American Cancer Society. 'What really has been difficult is trying to figure out how to get people to take notice of the message and engage in healthy behaviors.' Researchers at the Centers for Disease Control and Prevention and in Germany examined the habits of 23,153 German male and female participants aged 35-65 years who enrolled in the study between 1994 and 1998. At the start of the study, the scientists measured participants' heights and weights and asked them about diseases, lifestyle habits and diets. Healthy factors included never smoking; engaging in physical activity such as sports and bicycle-riding for at least 3.5 hours each week; eating a diet low in red meat and high in fruits and vegetables, and having a body mass index lower than 30. A person with a BMI of 30 or above is classed as obese. About 9 percent of participants practiced all four healthy lifestyle choices, and 4 percent practiced none. Roughly 35 percent of participants carried out a combination of two healthy factors. After an average of nearly eight years, researchers reviewed the participants' medical records for diagnoses of diabetes, heart attacks, strokes or cancers. Compared with those who practiced none of the four healthy lifestyle factors, those with all four showed a 93 percent reduced risk for developing diabetes; an 81 percent reduced risk for a heart attack; a 50 percent reduced risk for a stroke and a 36 percent reduced risk for cancer. Two healthy factors combined -- never smoking and having a body mass index of under 30 -- had a greater effect on chronic diseases than any other combinations of two, reducing risk by 72 percent overall. The scientists also found that each healthy factor on its own was linked to a reduction in chronic disease risk. A body mass index of lower than 30 had the greatest effect on decreasing risk for any chronic disease but particularly for diabetes. Never smoking reduced the risk of having a heart attack the most of all four factors. 'All of them are important, and trying to pick one is like asking someone to pick their favorite child,' said study co-author Dr. Earl Ford, a senior scientist in the Division of Nutrition and Physical Activity at the CDC. The study's findings are consistent with those of investigations that started in the late 1990s and are likely to apply to people living in the United States as well as those in Germany. Heart disease, cancer and strokes are the top three causes of mortality in the United States, killing an estimated total of 1.3 million people every year, according to the CDC. Diabetes is the sixth cause of death, killing 72,449 annually. In addition, many people live constrained lives in poor health because of these illnesses. 