Update 5.51pm: The Road Safety Authority has dismissed claims from one Independent TD, who says a big meal is as dangerous as drink-driving.
It has criticised the claims by Kerry TD Danny Healy-Rae, who says drivers are likely to fall asleep after a heavy dinner.
He says he personally doesn't drive after having a big meal, in case he might fall asleep behind the wheel.
But Velma Burns, a researcher with the Road Safety Authority, says drink-driving is by far a bigger risk.
"I would disagree that there are other overriding factors because the research shows that when alcohol is consumed that leads to other risky behaviour.
"I don't think it's a fair comparison to talk about the impact of a big meal on driving compared to the impact of alcohol."
Earlier: A Kerry TD has compared eating a big meal to being as dangerous to driving as having a few drinks.
Danny Healy Rae is maintaining his opposition to new laws that will see an automatic ban for first time offenders who currently get penalty points and a fine.
He has previously insisted that people having three glasses of Guinness and getting behind the wheel are not causing road deaths or accidents.
The Independent TD today insisted eating a big meal could be a factor in some road crashes.
"I for one anyway, when I'm going home out of here this evening, when I know that, I won't eat going in behind the wheel because I know what it will do.
"So like there are many other overriding, there could have been many other overriding reasons and causes of the accident as well as what you are saying the consumption of a small amount of alcohol," he said.