Been hearing about this one for at least a week...
It's obviously the product of well-meaning but exceptionally moronic factoid chefs who continue to barrage us with crap like this because they don't understand the difference between correlation and causality. It's not going to make a lick of difference whether or not you sit in the same room as your kid when he eats his Spaghetti-Os - the only way you keep your kid from becoming the next Nikki Sixx is to actually give a shit. And giving a shit means more than eating dinner together six or seven times a week instead of two or not at all.
Giving a shit requires communication, discipline and love. You need to communicate to your kids that your expectation of them is that they don't fry their brains before they're old enough to fully understand why they need those brains. You need to lay down the law of the land - that not living up to the expectations with regard to drugs is unacceptable. And you need to show them that you love and support them.
But eating dinner with your kids is only correlated with drug-free households. It's not going to magically drug-proof your kid, unless you also do the things I've described above. Watching your kid while he munches his asparagus spears isn't going to magically transform Sid Vicious into the next centerfielder for the New York Yankees.