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In 1979, lawyers for Dan White, on trial for the assassination of Harvey Milk, a San Francisco city district supervisor, and San Francisco Mayor George Moscone, argued that White’s diet of junk food and sugar contributed to a depressed mood and altered state of mind that led to the killings. White was convicted of manslaughter, not murder, and the “Twinkie defense” was born.

More than  30 years later, scientists say they may have found a connection between soda consumption and violence in teenagers. But not everyone buys the latest version of the “Twinkie defense.”

Researchers asked more than 1,800 Boston public high school students about their experience with violence – whether they had been violent toward  family members, friends or toward  someone they were dating. They also asked the students if they used tobacco, consumed alcohol and how much soda they drank each week.

The scientists reported that the teens who drank five cans of nondiet soda or more each week were more likely to behave aggressively than kids who reported drinking no soda. They found that the soda-guzzling students were 9 to 15 percent more likely to be violent toward others or to engage in aggressive activities, such as carrying a gun or knife to school. Teens who reported drinking alcohol or using tobacco showed the same risk of violent behavior.

The study was published today in the journal Injury Prevention.

When asked whether drinking lots of soda can cause teens to turn violent, several experts said no. But then there are many factors associated with both violence and  diets high in sugary drinks that more likely explain the connection.

“If they’re carrying a weapon and have been violent, that may be a marker of a less-stable lifestyle,” said  Keith Ayoob, associate clinical professor of pediatrics and child development at the Albert Einstein College of Medicine. “They may be less likely to be concerned with nutrition and physical activity. They may be less likely to sit down to family dinners. They may be using soda as a vehicle for alcohol.”

Additionally, many studies have shown that people who consume diets high in junk food like soda and low in more nutritious foods are more likely to be poor. The U.S. Centers for Disease Control and Prevention  cite poverty as one of the major risk factors for youth violence.The study’s authors note that they didn’t study the socioeconomic status of the teens who reported violence . For Dr. Martin Binks, clinical director and chief executive officer of Binks Behavioral Health in Durham, N.C., that’s a big problem.

“All of their findings could have been better explained in light of socioeconomic status,” Binks said. “Knowing potential relationships between socioeconomic status and the things they’re measuring, not including that data is a major omission.”

Sara Solnick, a co-author of the study, said there’s no reason to think that drinking soda causes teens to be violent. She said the study was simply intended to give researchers a better understanding of factors leading to youth violence.

“In the effort to try to understand violence and reduce it, you have to look at all factors impacting it, and diet could well be a factor,” Solnick said.