How much good fat is a good amount?

BODY weight plays a significant role in how much benefit children may get from consuming "good" fats, a new research suggests.
Consumption of omega-3 fatty acids — found naturally in foods including salmon, walnuts and soybeans — has shown to lower blood pressure and increase good cholesterol (HDL) in children eight to 15 years old.
However, parents looking to feed their children more of these foods should be mindful that as they gain weight they'll need more of these to make a difference, said lead author Lisa Christian, Associate Professor at the Ohio State University in the US.
Given fluctuations in BMI percentile measures as children grow, it would seem to make the most sense to base dosing on weight alone, Christian said.