Hopkins said parents needed to “get a grip” and tell their children they were fat.
She said: “Behind every fat child is a fat mother who should take full responsibility,” adding that children should “get less in their face and more on their feet”.
“It’s absolutely the parent’s fault that those children are fat. They need to look in the mirror, look at themselves, and realise it’s their fault,” she said.
“For me, every fat child lives in the shadow of a fat parent. And I think parents that say we have to protect their feelings, we have to look after them, we have to soften the blow [are wrong].
“It’s really important that parents get a grip, tell their children they’re fat, get together and sit down and do something about it.”
The mother of three said parents who refused to call their children “fat” at the risk of upsetting them needed to “man up and give those tough messages”.
Speaking to This Morning co-host Holly Willoughby, who said she would not want to call her child fat, the former Apprentice contestant said: “I believe that we’re far too soft, and Holly is a good example of a soft kind of parent that needs to really recognise there are children who are fat.
“We need to tell those children they are fat in order that we can start doing something about it, because tax payers are frankly sick of paying for a thousand children that were admitted to hospital last year because they have type two diabetes, because they can’t breathe at night because their own body weight is crushing them and that’s the problem we’ve got.
“So all of this nicety, being kind, teaching them how to cook good meals, that’s not the answer. The answer is: you are fat, you as a parent are fat. Get a grip, do something about it.”
Poulton, who argued that children needed to be spoken kindly to, and be taught to make healthier meals at school, told Hopkins: “You would be compromising your child’s mental health if you start labelling them the way children would. Katie, you really need to look at yourself.”
Hopkins replied: “I’m looking…but not at you darling. When you’ve got a zebra in a wig shouting at you, really it’s too much.”
Hopkins, who took part in The Apprentice in 2006, first appeared on ITV's This Morning in July, when she made a number of outrageous comments claiming she would never let her children play with other children who had "lower class names like Chardonnay and Tyler".