The most common killers in the United States are preventable with some slight lifestyle changes, health experts said.

According to the Centers for Disease Control and Prevention, the top three leading causes of death in 2000 were heart disease, cancer and stroke. The top three actual causes of death — the activities leading to these causes — were tobacco use, poor diet with physical inactivity and alcohol consumption.

“It is now estimated that somewhere around 430,000 people die annually [in the United States] as a direct result of smoking,” said Frederick Gibbons, professor of psychology.

Gibbons said most young adults try smoking, but whether that leads to drug experimentation is influenced by social factors, exposure to tobacco use in advertising and other media, availability and even genetics.

“People metabolize nicotine at different rates … some find it pleasurable or addictive, and others don’t,” Gibbons said.

The CDC reported for smokers in 2000, 49 percent of conditions resulting from smoking were chronic bronchitis. Emphysema was second-most common at 24 percent.

Gibbons said it may take 30 years or more for some of these conditions to surface, which is why smoking continues.

Poor diet and lack of physical activity is the second contributor to preventable deaths in the United States. Obesity is on the rise and is predicted to overtake tobacco as the leading cause of preventable death, said Greg Welk, assistant professor of health and human performance.

“[Obesity] has more than doubled in adults in the past 20 years — with over 60 percent classified as obese —and tripled among children,” Welk said.

Welk said health benefits come from being fit and not necessarily from being normal weight.

“It’s not so much obesity that causes problems, but rather the lack of physical activity,” he said. “People that are overweight but physically fit and active have lower risks than people that are normal weight but are inactive and unfit.”

Lack of physical activity can lead to coronary heart disease, cancer and stroke, Welk said.

The third leading cause of preventable death in the United States is alcohol, the CDC reported.

Frank Schabel, assistant professor of health and human performance, said binge drinking is five alcoholic beverages in a row for men and four beverages for women.

The National Institute of Health reported 25 percent of college students admitted to academic consequences of alcohol, including missing class, falling behind in school, doing poorly on exams and papers and receiving lower grades, Schabel said.

The same report indicated 60 percent of college students did something they regretted after alcohol use. Fifty-five percent admitted to driving after drinking and 50 percent to riding with an intoxicated driver. Forty-one percent participated in unplanned sex and 11 percent got in trouble with police.