If you’re trying to lose weight, what motivates you will have a significant impact on whether or not you’re successful. Losing weight within a week to look good at a wedding, for example, is probably not the best reason to jump-start a healthy lifestyle.

Instead, having the desire to change your ways for the sake of long-term health can make all the difference. Teens who put their mind to losing weight — and succeed — differentiate themselves from those who try but fail, by being motivated by intrinsic reasons rather than social acceptance, according to a new study. The study, published in the journal Childhood Obesity, found that overweight teens who successfully lose weight do it for their own sake rather than for the superficial desire to please parents or others.

“Most parents have the view that their teen is largely influenced by other people’s perceptions of them,” Chad Jensen, a psychologist at Brigham Young University and an author of the study, said in the press release. “Our findings suggest that teens have motivations that are more intrinsic. One implication is that parents should help to focus their teen on healthy behaviors for the sake of being healthy more than for social acceptance.”

In the U.S., around one-third of all adults are obese or overweight. Childhood obesity, meanwhile, has also been ballooning (but has improved recently thanks to Michelle Obama’s Let’s Move! program) — it has doubled in children and quadrupled in adolescents in the past three decades. According to the Centers for Disease Control & Prevention (CDC), 21 percent of American adolescents (aged 12-19) are obese or overweight. Because of this obesity epidemic, parents and teens alike can take note of this study’s findings: Motivate yourself by the desire for good health, and you will go far.

The study, the authors write in the abstract, aimed to provide “an in-depth analysis of behavioral strategies, psychological factors, and social contributors to adolescent weight loss and weight loss maintenance.” The researchers studied participants in the Adolescent Weight Control Registry (AWCR) — examining the success stories of 40 formerly obese kids. These teens, on average, lost around 30 pounds and were able to maintain their lower weight for a year.

Sixty percent of these successful teenagers reported that their own health was their first and foremost motive. Forty-three percent of them, meanwhile, said that being accepted by their friends or peers was a factor, one way or another. But ultimately, almost all of the teens stated that it was their own decision to lose weight — even though they were helped by parents to create healthier meal and snack plans. In addition, the time period that the teenagers decided to lose weight — particularly “big change” periods, like the transition of summers or changing schools, helped a lot.

“There were some periods, like a transition to high school or to college, where we saw groups of teens who lost weight in those important periods,” Jensen said in the press release. “It’s sort of an opportunity to re-make yourself. There’s a lot of change going on, so some teens decide to make a change to be healthier.”

Most importantly, the teens in the study all took their time to lose weight. Not many had unrealistic expectations to drop 10 pounds in a week, which is often harder to sustain. “None of these teens in our study lost weight in a hurry,” Jensen said in the press release. “Their advice to other teens is to stay the course and sustain it over the long term. For most of them it was just a pound or two a week.”

Source: Jensen C, Duraccio K, Hunsaker S, Rancourt D, Kuhl E, Jelalian E. "A qualitative study of successful adolescent and young adult weight losers: implications for weight control invervention." Childhood Obesity. 2014.