The guidelines were developed in response to growing concern about teenagers' use of unhealthy methods to lose weight.
Quick, substantial weight loss methods can trigger medical consequences such as unstable heart rate.
Also, teenagers who diet in ninth grade are three times more likely than their peers to be overweight in 12th grade, the researchers said.
"Scientific evidence increasingly shows that for teenagers, dieting is a bad news," said lead author Neville Golden, Professor at the Stanford University in California.
The calorie-counting diets can deprive growing teenagers of the energy they need and lead to symptoms of anorexia nervosa, which may even become life-threatening.
Parents and doctors should not encourage dieting, and should avoid "weight talk" such as commenting on their own weight or their child's weight.
Instead parents should help their children develop a healthy body image by encouraging them to eat a balanced diet and to exercise for fitness, not weight loss, the researchers stated.
Further, they should also never tease teenagers about their weight. Negative comments about weight can also be detrimental to a teenager's health.
"Mothers who talk about their own bodies and weights can inadvertently encourage their kids to have body dissatisfaction, which we see in half of teenage girls and a quarter of boys," Golden noted.
Such dissatisfaction is associated with lower levels of physical activity and with use of vomiting, laxatives and diuretics to control weight.
Families should eat regular meals together, the researchers suggested, adding that eating family meals is likely to prevent against weight problems, said the paper published online in the journal Pediatrics.
