The study found that the greater the child's Body Mass index, the lower they and their parents scored their quality of life.
The children's quality of life, as reported by their parents, was comparable to young people diagnosed with cancer and worse than a group of Taranaki children living with a chronic condition which required daily treatment.
Reported quality of life was worst in those who experienced breathing pauses while sleeping, headaches, difficulty getting to sleep or developmental problems.
Study co-author, Liggins Institute researcher and Taranaki paediatrician Dr Yvonne Anderson said the findings highlighted how important it was that obesity programmes involved psychologists.
"This study highlights that a large proportion of children and teens struggling with weight issues are also highly likely to be affected by psychological problems, and in turn, lower quality of life."
But because the findings came from a group who were seeking help with their weight, they could not be generalised to all of society, she said.
"We hope these findings serve as a reminder that we all need to work to reduce the stigma associated with obesity.
"It is really important that we do not see obesity as a single condition. It has many contributing factors, can affect individuals in many ways, and undertaking respectful, non-judgemental, and individualised assessments is critical for any type of meaningful engagement."
This study is the first in New Zealand to assess quality of life in young people seeking help with weight issues.
The study was a collaboration between the Liggins Institute based at the University of Auckland, Taranaki District Health Board and Sport Taranaki.
Read the full study here.