What's motivation got to do with weight loss?

Researchers at the University of Kentucky and University of North Carolina at Chapel Hill examined two types of motivation, autonomous and controlled, and their relationship to adherence and weight loss in a 16-week Internet weight-loss intervention. To measure the 2 types of motivation, a Treatment Self-Regulation Questionnaire was used to identify those participants motivated by intrinsic and extrinsic controls such as feeling that performance is the best way to help oneself and making changes for personal reasons (autonomous motivation) and those participants motivated by only external controls such as perceived pressure from others and feelings of guilt (controlled motivation). Motivation for weight loss was measured at baseline and 4, 8, 12, and 16 weeks. In addition, study participants recorded their food intake, exercise, and body weight through an on-line self-monitoring system weekly throughout the study.

Over half of the participants (37 of 66) lost 5% of initial body weight at the 16-week follow-up. To examine the relationship between the 2 different types of motivation and weight loss, the sample was divided into those who had and those who had not lost 5% of initial body weight by 16 weeks (37 and 29 participants, respectively). The researchers found that the majority of participants had a significant increase in autonomous and controlled motivation between baseline and 4 weeks, though it's not clear what caused the increase in motivation at 4 weeks, the face-to-face session given at the start of the study, early success with weight loss, or something else. Although motivation increased initially for most participants, the group that went on to achieve a 5% weight loss sustained their autonomous motivation between 4 and 16 weeks, while the group that was less successful experienced a significant decrease in autonomous and controlled motivation over time.

The authors also found that autonomous motivation at 4 weeks was a significant predictor of adherence to self-monitoring and weight loss. Furthermore, this increase in self-monitoring appeared to be a way in which autonomous motivation led to better weight loss. The authors found a positive correlation between weight loss at 4 weeks and higher levels of autonomous motivation especially when compared to participants who had higher levels of controlled motivation. .

Writing in the article, the authors state, "It appears that the time period between 4 and 8 weeks may be an important window for weight control programs to consider using techniques designed to enhance autonomous motivation, including giving more intense support or different types of interventions, such as activities to enhance autonomous motivation or contact from a weight-loss counselor in the form of e-mails, phone calls, or face-to-face meetings."

"It is possible that motivation measured a few weeks after the study has begun more accurately captures motivation than baseline motivation for weight loss since participants have become familiar with the behavior changes that will be necessary for weight loss and can better gauge their motivation for making those changes."

"These findings suggest that building motivation may be an effective means of promoting adherence and weight loss."