It's a mantra repeated by parents all across Britain: "Clean your plate – or you'll be having it for breakfast."
But now experts claim the stern words may be fuelling an obesity epidemic.
In research that is bound to leave put-upon mums and dads slapping their foreheads in despair, dieticians in America said parents may be to blame for overweight children.
They say ever-growing portion sizes mean children are being pressurised into eating more than they need which means they don't know when to stop.
I might be missing something here, but surely the issue is about putting too much on your children's plate in the first place, rather than insisting they should finish it?
Anyway, Katie Loth, a dietician at the University of Minnesota in Minneapolis, U.S., told HealthDay: "I was surprised at some of the parent behaviours, like feeling that their children should clean their plates and not waste food.
"In the 1950s, cleaning your plate meant something different.
"Portion sizes have got bigger over time, and if you encourage kids to rely on environmental indicators, like how much food is on their plates or the time of day, they'll lose the ability to rely on internal cues to know whether they're hungry or full."
Ms Loth studied data about 2,200 teenagers and 3,500 parents. She found that fathers were more likely to pressurise their children into eating all of their food than mothers were.
She also discovered that teenage boys were more likely to be put under pressure to finish their food than teenage girls.
In another groundbreaking (sic!) revelation, Dr Brian Wansink, of Cornell University, in New York, suggested that the key to avoiding over-eating at all-you-can-eat buffets is to take a smaller plate.
He observed the behaviour of slim people at buffets and compared it to the behaviour of larger people. He noticed that thin people were seven times more likely to take a small plate and that the thinner diners tended to look at all of the food on offer before choosing what to have. By contrast, larger diners tended to consider each item individually.
He told HealthDay: "Skinny people are more likely to scout out the food. They're more likely to look at the different alternatives before they pounce on something.
"Heavy people just tend to pick up a plate and look at each item and say, 'Do I want it? Yes or no'."
More on Parentdish: Are we over-feeding our children?
What do you think?
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